The Ecological Cost of a Polytunnel
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- Опубликовано: 6 сен 2024
- Polytunnels are very useful spaces to grow vegetables in, but they have an ecological cost, especially in terms of greenhouse gas emissions during their manufacture. But how do the emissions from making the polytunnel plastic and frame compare to importing food from warmer places?
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Very interesting ecological cost benefit analysis. I would say I'm solidly in favor of use of plastic as season extension, despite the degradation from the sun making it a temporary structure. Sure, a glass greenhouse will last a lot longer, but it's also a much larger investment unless you can get a hold of and recycle old window glass and framing. The ecological cost of a polytunnel still easily repays itself in most cases, and like you said, compared to most absolutely stupid uses of plastic like disposable utensils, shopping bags and other things that easily slip into the ocean and become micro plastics and choking hazards a polytunnel is definitely benign. The only thing that was a bit confusing was your slide about the burning of the plastic... You said burning 1kg of plastic produces 3kg of CO2. Sounds like a violation of the law of conservation of energy (mass), but I figure you must mean that to fuel the fire plus transport it to a burning facility incurs those extra kilos?
Thanks for the comments, I agree with everything you said.
Sorry about that one slide relating to the burning of the plastic, as I had wanted to put in the details of the calculations, but it was too late and I was too tired to figure it out - and was afraid of making a mistake.
Essentially it comes down to chemistry and the atomic mass of carbon, hydrogen and oxygen. The plastic (C2H4) has 2 atoms of carbon (that have an atomic mass of 12 each), for every 4 atoms of hydrogen (with an atomic mass of 1 each), so the carbon makes up 24/28 or about 86% of the mass of the plastic. So burning one kg of plastic would release 0.86 kg of carbon. But each carbon atom would need to be combined with two oxygen atoms (which have an atomic weight of 12 each) to form CO2 - so the carbon would be 12/44 or about 27% of the mass of the CO2. So take 0.86kg carbon and divide it by 27% (or divide by 12 and multiply by 44) and you get 3.15 kg of CO2. I think that is how it works at least.
So a simple answer is the plastic is mostly carbon, but to be a gas it has to combine with oxygen which is much heavier.
C02 has 2 Oxygen atoms for each Carbon atom. I didn't take chem, by I'm sure the Oxygen has some weight.
@@christal2641 Yes, each of the oxygen atoms has an atomic weight of 16, and the Carbon atom weighs 12. So that is 16+16+12=44 atomic weight for the CO2 molecule. The Carbon is 12/44 of the weight or about 27% of the weight of CO2.
This makes it a bit confusing when talking about carbon and CO2 (which are unfortunately often interchangeable when we speak in general terms about sequestration). In simple terms sequestering 1kg of CO2 means that about 275g of Carbon has been put away or sequestered, or for every 1kg of carbon sequestered, that means that 3.7kg of CO2 has been pulled from the sky. And the opposite if the material is burned.
The plastics used in Polytunnels is of positive ecological costs-investment factor because the oil used in making it is not used in a one time use as gasoline, diesel fuel, kerosene, alcohol, etc. But used in a reusable-recyclable ussage plastics which can be converted into oil or reused as recycled plastic. The problem now lies with PLANNED OBSOLESCENCE, like what happened to nylon which was originally formulated to last a lifetime and then the DUPONR chemists were ordered to make it weaker. In fact, all kinds of plastics can be made to last indefinitely by using their original formulas and UPGRADED and not degraded. The plastic used to seal coat the underwater NORDSTREAM RUSSIAN GAS PIPELINE is polypropylene which uses the original formula and upgraded/reformulated to last as long as it exists. The original fiberglass-reinforced acrylinc plastic used in the New Alchemy experimental ecological off-grid and self-contained greenhouse designed and built by Professor John Todd is still standing today AS GOOD AS NEW!
@@darthvader5300 Interesting stuff. another factor in it all is that the plastics, as far as I understand it, are made form compounds that are extracted in the process of refining crude oil to gasoline or some other energy source. the industry has to remove all this stuff, and the idea of adding value to the potential waste apparently led us to plastic. In other words, plastic and gasoline are created from two different parts o the same crude source. So the amount of plastic in the world is directly related to the amount of gasolebne (and diesel?) used. If the industry didn't make plastic as a byproduct, I wonder what would become of these compounds.
When calculating the "payback period" for the structure it seemed like you used the amount of food that you could grow in the polytunnul but I think you should have used the difference between the amount of food grown in the polytunnel and the amount of food grown on the same land area but without a tunnel.
Good point. In ways it would be better to do what you suggest. I should have clarified that I have more than enough land outside, and am assuming other growers do as well, but that the vegetables that I can produce in the polytunnel cannot be grown outside (either wrong season, too windy or too cool). I am assuming that people will be purchasing vegetables off season, and warm season crops like tomatoes, if they cannot be produced elsewhere. And that people will reject salad leaves in the winter that have been bashed by the wind. This is what I have found with most people (including my own family), what can be grown here in Ireland without a polytunnel, will only satisfy part of the diet for part of the year. With a polytunnel there is additional supply that will fill that additional need/desire and prevent purchases from Spain - that is what I was basing my calculations on.
But I should have clarified that in the video, or at least also calculated the payback period as you suggested. As a general rule of thumb, a polytunnel doubles the yield in a given area of land, so the payback period would be double what I've calculated.
@@REDGardens Right, I was sort of thinking double the production and double the payback period would be a reasonable approximation, thanks for confirming that. I understand the point about out-of-season demand and am not down on greenhouses but wonder if food preservation would be a less energy-intensive and more food secure means to the same end of feeding people, even if it means a loss of certain things at certain times of the year. But that would involve changing cultural attitudes and practices which seems to take some time. I would be interested to see an ecological footprint analysis on passive solar greenhouses as compared to polytunnels as well. Someone in the comments was saying you are originally from Canada, specifically southern Ontario (maybe you mentioned it in the video and I missed it), which is very interesting to me since I am in Toronto. Anyway, thanks for taking the time to respond and I really enjoy all of your in-depth content and thoughtful commentary, one of my favourite channels.
@@MrCjallaby How to satisfy out of season demand, and getting people to adapt their diets to what can be produced within the local climate, are interesting issues. In ways I see the polytunnel providing a stepping stone along the process. It means that I can produce some of the warm season crops that so many people like, such as tomatoes, but can't be reliably grown outside here. It also means that I can supply greens and other crops when root vegetables, leeks and kale are the only other crops available from outside. And better quality greens (aka not wind damaged!). I think that without these buffers, most people would find it difficult to start to shift too a local supply of vegetables. It may be a bit backwards, but I think we need to get people to start the process, adapt to a different supply system, and support the local farmers, and then to slowly broaden their palette and encourage them to preserve, as you suggest. Polytunnels are the easiest and perhaps least environmentally damaging way to do that.
My family home is in Caledon, NW of Toronto, and I went to University of Toronto and lived in the city for a while. A great city, that I am still fond of.
@@MrCjallaby I have canned, frozen, and dried food I've grown, and in our humid summers, even food drying takes some energy. (There is ALWAYS some nutrient loss, though cooking/canning tomatoes increases availability of lycopene.)
They are using green houses in Spain as well. that doubles the cost of greenhouse effects you calculated.
it has been a year and nobody has left you a shitty comment for your shitty comment.
So here it is. Yours was a shitty comment.
I love that you are looking into the often unseen costs of food production and giving us some real numbers
Thanks. I think it is important to at least have a sense of how lots of different aspects compare.
You are the only one who addressed the us of plastics in greenhouses. Most growing videos I've seen, by ecological growers, never addressed this issue. You may have overlooked in your calculations, the amount of carbon sequestration operated by the vegetables over the life of the plastic, that offsets the carbon released in producing it.
Glad you appreciate my efforts, and I also have noticed how most other people don't address this issue.
The amount of carbon sequestered in the vegetables growing in this tunnel is an interesting one. I didn't include it in my calculations as this carbon is part of the living carbon cycle, and I wanted to focus on the amount of additional fossil carbon that would have been added to the living carbon cycle, as that is the stuff that is critical from a climate change perspective.
The vast majority of the CO2 absorbed by the plants will be released again as soon as the vegetables are eaten (returning as CO2 to the atmosphere with our breath), or when the remains of the plant is composted, where a lot of the carbon will also return to the atmosphere.
It could be argued the increase in organic matter in the soil, as part of the plant growth or with the compost added, could be seen as offsetting the emissions released in making the polytunnel, but only of the organic matter increases, and states at a higher level.
Someone else suggested that the increase in productivity of vegetables by covering the garden with the polytunnel, could also be seen as a once off 'sequestration'. It would be interesting to estimate these figures, to see how they compare to the original emissions.
@@REDGardens Certainly! But I can rest easy with your proof in the video without pushing the analysis any farther.
Oh by the way, greetings from a Frenchie who lived in Toronto for a while, back in 1983.
Thank you so much for such an intelligent "accounting" of available alternatives for commercial crops. Polyfarms near urban centers are the future!
Here in Minneapolis, 45° N., we have lots of sunny winter days well below 0° C. We also got over 4' of snow in Feb., March, and April. this year. That much snow is tough on plastic sheeting. But for a back yard farmer, there are cheap options using similar principles.
Our plantable yard is about 3000 sq.ft. We've been growing hardy fruits & annual veggies for 8 years. Last fall we added a lean-to style twin wall plastic sided cover for my new 8'X3' bed. For a lark, I tossed in some lettuce seeds and watered it as winter closed in early in Nov. Temps went down to -25° C.
Last week I opened up the vertical sides and saw a large swath of first leaf stage lettuce seedlings, which I can begin cropping in mid May! The two sheets of twinwall cost about $35@. The treated 2x4 lumber was mostly leftovers from other projects, we already had the screws for treated wood, so this was a cheap and simple project which should last more than a decade.
The beauty part for us is that travel time to the nearest grocer is 45" each way by bus. My fresh greens should survive April-November most years here. There's no supplemental heat or light or insulation.
We live 3 miles from downtown in a big city and in 8 years have managed to fill our freezer with fruit to eat year 'round, and have vegetable beds, which help us be more food secure.
Other folks are building cold-frames re-using old glass windows -- caution: be SURE there isn't lead paint on them. Hardware stores in old cities have a head paint I indicating crayon that tells you instantly. Our walnut tree makes using glass unwise, but if you aren't near a tree or where a passing vehicle could fling up a stone, re-using old windows is a great option.
So, if you long to grow some of your own food, and all you have is a sunny yard, or even a sunny window, start!
Sounds like you have a great setup, and are being really productive with your growing space. You are right, there are lots of ways to extend the season, especially in that kind of climate. Elliot Coleman's books can be a great resource for this. Where I grow, there is much less sun in the winter, but also rarely below freezing, so there are lots of possibilities for winter growing, even if things are slow to grow.
Definitely different designs for different climates
Hi Bruce! I'm glad you talked about Maine where I'm from. I can say in Maine, you need protection and the heat retention as you would in Canada. Otherwise you are stuck with short season crops or extreme cold hardy ones. I once had a cold-hardy kale plant from Fedco Seeds that stayed out all winter in a snowbank and was fine come next spring! The rabbit enjoyed it very much with no complaints!
It is interesting how different the winter is over there. When I first read Coleman's book I thought I would do a lot of what he recommends, but then realised that I am currently growing in a climate that doesn't get anywhere near as cold, and in many cases simple wind protection can do a lot for having food throughout the winter.
Thanks, as always, Bruce, for your careful thought and analysis. I recently did some back-of-the-envelope calculations to see if some of my garden supply purchases make sense, particularly some plastic items that I hope to use for at least five years. It's pretty amazing how quickly the benefits of simply walking out your back door to feed yourself with fresh produce can make up for and exceed the costs of all sorts of transportation, packing, refrigeration, waste in otherwise commercially purchased food. Every little bit helps, especially when it leads to an overall change in attitudes and assumptions. Keep up the great work!
Thanks! Those back of the envelope calculations can be great! Really important to keep things in perspective. It is amazing how much growing your own food can achieve in reducing reducing problematic issues. We shouldn't be frivolous with the equipment and supplies that we use in our gardens, but we should also not be too purist that it prevents or reduces our productivity.
Thanks for the video! I recently found your channel, its a damn shame you don`t have more followers. Great work that you do, greetings from Canada!
Thanks. Glad you found my channel! Where in Canada are you?
@@REDGardens I live in Saskatchewan. Getting excited for the season, but my plants will be inside the house for some time yet! Thanks for the response!
@@vincentplag I am from near Toronto originally, and just heard from my parents that it is still snowing there!
A fascinating way of looking at things.
It staggers me how many plastic things are delivered in plastic packaging, which it's self is packaged in more plastic.
Guttering for example.
The amount of plastic is indeed staggering, and so much of it is close to useless.
As an Architect , I used to do embodied energy calcs for construction materials.
Never thought I would find someone who equally loves to get so deep down into the detailed science and maths.
Apparently beetle larvae can digest plastic (so far, experiments are with styrofoam), so burning plastic at the end of its life / dumping into landfill may become an unnecessary evil.
Keep up the excellent work.
Love your videos.
Hey, thanks for the comment. Just so you know, I studied architecture, and worked in the field for a while, but never lost that desire to really try to understand what was going on.
Biological breakdown of plastic by larva and bacteria are still in the development stage. It's such a recent discovery that there really aren't any developed practices. It will be a while before best practices are developed and there will also probably be breeding/genetic modifications for more efficient plastic breakdown that will take a while.
I have been growing greens hydroponically under led shop lights in my basement. Our electricity comes from hydro-electric. I am freezing my excess and consuming or giving away excess product to my community. Parts other than lights, 2 concrete mixing tubs, and one 2'x4' Styrofoam panels. Dry fertilizer that I hydrate on site. I don't know how to calculate the carbon foot print, but I would guess it is very low. All components can be used year after year. Each successive year represents almost nothing in carbon foot print.
That sounds like a very cool setup. It is interesting to think about this stuff in terms of carbon or ecological footprint. I suspect that the main carbon cost from your setup would come from the fertiliser, especially as it is the only resource you use continuously (apart from the hydro-electric power.
@@REDGardens Yes, the fertilizer is the ongoing carbon creator. Assume I get 4 crops per year, each concrete mixing tub is 9 gallon and gets 60 grams for a total of 480 grams (roughly one pound) per year. I buy it in 75# batches. I actually am now running three of these system, plus a seed starting unit so that when I take down one system I have young plants ready to go. However my plants eat carbon dioxide and give of oxygen, maybe this system it is actually carbon neutral. The quality of the greens I grow is exceptional. Of course everything we do is a tiny drop in the bucket to the big polluters.
@@silverfoxes65 Interesting - doesn't sound like a lot of fertility use. Unfortunately with the Carbon Dioxide being absorbed by the plants, it will only be released into the atmosphere in the breath of the people eating the greens. So only a short cycle of sequestration, not sufficient to offset to the other emissions. Yeah, everything is a tiny drop, but the more people who do these things, the better. That is why I think it is so important to share our experiences, and our vegetables!
Love the way you break down the whole process here. This is the realest over standing we all need to have as far as the choices in being a consumer let alone the honest way we need to under stand our ecological output regardless of our business, including green business such as garden farms not just agricultural and industries. Fantastic presentation, Thanks a Ton;)
Thank you. It means a lot to know that some people really appreciate my approach and videos.
That we do brother, its interesting how many approaches there are. I know some old timers that teach classes and have no idea what N-P-H or B1 or micro/ macro nutrients are; I get that completely we only just began to get deep into chemistry. Hence why I think more hen ever every technique needs to be compared and contrasted over and over especially for each environment and against scientific method if and when possible. Especially since I and so many are for natural or organic methods of farming like poly or perm culture as well as no till so to see your variations pros and cons, is an immense wealth of knowledge waiting to be further analyzed and regarded by many more not just yourself. We're all (the serious few) aware the high costs from labor to investments to the videos, So's as I've said before Health & Prosperity to you and Your's.@@REDGardens
Thanks for the breakdown of your poly tunnel CO2 costs. As I think about a future greenhouse project, your video has given me some important aspects to consider. I think the concerns with plastic isn't only about CO2, but about how it persists in the environment, only becoming smaller pieces and killing wildlife who eat it or become tangled in it.
I think Bruce addresses the persistence issue by specifically mentioning incinerating the plastic at the end of its usable life.
I was going to address the problematic issues of micro plastics, but dropped it from the video as it was getting too long and complicated. It can be an issue, especially with old plant pots, plastic fertiliser and storage bags and other random pieces of plastic breaking down and ending top in the soil. With the big plastic sheets, it is much easier to control, and hopefully reuse then dispose of or recycle properly. Personally, I am more concerned about the tiny bits of plastic that end up in the compost!
Great Video. I watched a bunch of your videos about composting and gardening a couple years ago, but I forgot to click subscribe, and at some point I deleted my watch history and couldn't remember your name, so I was really happy when this video showed up in my recommended list today. The first thing I did was hit the subscribe button.
Glad you found my channel again!
I think your breakdown of the ecological costs that come with your style of gardening is very noble of you. It also shows how much you do care about your craft and the earth. Ultimately I think that the most harmful part of using plastics is the burning of them as well as the possibility of them becoming lost in the ocean/ecosystem. The burning of plastics can emit low levels of toxic pollutants such as dioxins, acid gases, and heavy metals. As long as they are done within a safe and well monitored waste-to-energy or recycling plant there isn't too much ecological damage being done. But if the plastic is burned by someone in their backyard then all of the harmful toxins will be released into the atmosphere. And we all know the damage that is done from plastic materials being littered throughout our environment, so as long as you are handling your waste in a responsible way your ecological impact can be limited. I think your videos are great and I am now an avid watcher. Keep up the great work!
Thanks. Glad you appreciate my efforts. I agree that the most harmful is likely the low temperature burning - which typically happens in backyards to get rid of waste. On of the reasons I wanted to make this video is there is this growing perception of all plastic being bad, and potentially seeing all uses as equivalent. I think that plastic is a wonderful material, but we use way to much of it, and dispose of it in problematic ways.
nice tunnel. how does it fare in gales? and snow. I'd like one, but i'm on a ridge. Storm Doris, 2years ago, ripped a bit of concrete sheet off my hay barn, and bent the scaffold pole my wind turbine was on. I have a small polycarbonate green house, it is resilient to storm damage, as long as i can find the sheets again, after blow outs.
I have had to put up a windbreak around the tunnel as it is in an exposed spot, and we lost a few tunnels on that site in a storm a number of years ago. The structure does flex quite a bit, but it is the plastic that can be ripped off.
The steel frame is not as much of a problem as plastic because of the life time of two objects. The sheet cannot be used more than several years due to UV degradation. On top, the steel frame can be recycled back with less energy (compared to making the steel from scratch) while there is no real recyclable plastic (infinitely recyclable like metal).
Thanks for this analysis. This video made me subscribe to your channel. We need more people like you!!!
Thanks for the supportive comment. I agree that the frame is not such a problem, though I wanted to be conservative about the impact. I have also seen a number of polytunnel frames lying around rusting, so I recognise that this might be what becomes of my frame. The plastic should last at least 7 years as it is UV stabilised, one sheet on my other polytunnel is 8 years and is of lower quality/strength, but you are right plastic is not really recyclable, at least not for more than a few cycles.
"Stupid uses of plastic." Even though there were disposable diapers when I raised my kids, I used cloth. Am 70 years old now, and still have some of those diapers, used for washcloths, dust rags, rags for washing windows and vehicles, etc., and some have been added to the compost bin because they were too far gone. Am disgusted by young adults who use the disposable diapers because they "wouldn't get caught dead putting their hands into the toilet" to rinse the poo out of cloth diapers. Yet they don't seem to mind buying a new vehicle every 4-5 years (mine is 30 years old), or aborting babies (murder in MHO). I admire the research you did, and acknowledge plastic does hinder the environment. Reused is key here, and also the weight of the usefulness in growing something that sustains human life, but also keeps OTHER Co2 factors DOWN.
Thanks for the comment, and I appreciate your take on stupid uses of plastic. I like how you put it to compare the usefulness of growing something and keeping other factors down.
You do the co2 emissions calculations, but don't plants themselves feed off that? So not only do the plants grown inside cause less driving/transportation, but they also clean the air by themselves thus adding even more benefit?
I didn't include the CO2 from the plants, as it would only be 'sequestered' in the food and plants until we (or some other creature in the compost pile) eats them and breaths out the CO2 again. That is the living carbon cycle. What I was concerned with here is adding additional CO2 to the system from the ancient fossil reserves.
Plants only "store" CO 2 they don't take it out of the cycle. Trees are good at "storing CO 2! as they grow slowly and decompose slowly or can be used for buildings and furniture which are also long lasting. Most plants grown in greenhouses/ poly tunnels are annual. That means that the CO 2 is also released rather quickly, either by eating them or decomposition.
I've just been down to the shopping mall - the plastic crap housed there is a TRUE waste of resources. Plastic is a wonderful material and this would have to be one of the more sound ways to use it - not to mention the seriously pleasant workspace it provides. We're on the way out anyway Bruce - enjoy the polytunnel! Great video, as usual.
Thanks! It is so sickening to see such wasted use of potentially really valuable materials, and to have the careful and considered use of plastic for serious benefit put into the same category as the rest of the frivolous use.
Well done for bringing up the subject. I think the real issue is in the disposal of the plastic. More than 70% of the plastic products release chemicals that act like estrogen - even before it is exposed to sunlight. These hormone-like chemicals are already having profound effects on living systems. Microplastics are detected in the bloodstream of all humans.
You are right about the issues of disposal, and potential of releasing chemicals. I was going to mention those issues in my video, but cut them as it was getting too long, and going off topic. My main point was that not all plastics are the same, and not all uses of plastics are equally problematic.
I have not seen any data about the release of problematic compounds from polytunnel plastic which is very stable against sunlight degradation, but there is a lot of research developing about the issues with containers that are in direct contact with water and food we consume. With the polytunnel plastic, the plants are rarely/never in direct contact with the plastic, so any leaching would be into the soil at the edge of the tunnel. There could be some issues with this, but I have never seen any data on this so it is all speculation - something to be aware of, but I suspect that the any contamination would be minuscule compared to the contamination we already get from other sources.
Micro plastics are an issue, but in the garden it is mainly from the plastics that end up in the compost, and plastic bags and pots that I use around the gardens. I have seen this type of degradation of plastic bags that I was using to store material, with little pieces going everywhere. With the polytunnel plastic, I doubt there would be very much, if any of this physical breaking up into tiny pieces. I've seen this stuff exposed to all kinds of stresses and so far have not seen how it would become a significant source of micro plastics. That doesn't mean that it won't happen in time, and why I will be careful to properly recycle sheets when I am done with them, but compared to other really problematic sources (like out clothes) I think the polytunnel plastic is very low risk.
I hope you get to try out the in-ground / partially submerged type of greenhouse. I'm sure that your analysis of it and experimentation would be invaluable to so many out there.
I have looked into those and they seem to work really well in some contexts, such as the cold middle of North American. Where I am located, the sun in the winter time is just so low in the sky, that it would not shine on the bottom of the submerged polytunnel for most/all the winter. And the temperatures don't get so low most of the time, rarely does it stay below freezing for any length of time. So a simple sheet of plastic over the garden at ground level works really well. We also have the issue of a high water table on our site and lots of rain - if you dig a hole it fills with ground water for a lot of the winter! Having said that, it would be interesting to do a comparison, but I would have to wait until I had the surplus cash to fund that experiment.
With changing climatic conditions the green house is an essential part of a stable food production. The greenhouse is a season extender and a zone pusher and . Poly tunnels are some of the least expensive forms of greenhousing. The cost of glass is is prohibitive for the average market gardener starting out but would last several generations.
I agree completely, especially about the stable food production.
Fantastic education. The part with Eliot Coleman was very useful for my decision making
Cool. Eliot Coleman is amazing. He did some remarkable stuff, and inspired many people.
Fantastic analysis, you guys know more than just sirop d'erable.
Thanks. Once you know maple syrup, a lot of the rest of the world is easier to understand ;)
This is a great video , alot of things to think about. Terri and I have purchased a mini green house this year so we will let you know how it works. Last year we made a simple one using old wooden open end book case with plastic over it it worked , but it had a hard time with winds . So this year we got a mini glass one , will let you know how it does.
Thanks! Always good to experiment!
Polytastic film. Been pondering ethics as well but there are no alternatives yet that are affordable for small enterprises limited budgets. Look forward to your next topic.
Good point.
i wonder how long it takes for a glass greenhouse to beat a plastic one in terms of co2 cost. The glass could technically last forever but the wood would need to be replaced every 20 years.
winter storm damage would be an issue for either glass or plastic and the difficulty in cleaning up shards of glass may need to be considered
Good questions. The embedded energy/CO2 in glass woful be higher I think, and the structure would need to be a lot stronger and more rigid, but it would last a lot longer, so long as it doesn't break. It would be an interesting thing to explore or calculate.
I bought a large (Aluminium) glasshouse (30M x 30M) from a Nursery that was being converted into a housing estate :). So I saved it from demolition, and got myself a very cheap, huge, covered space and I have avoided having the effort/cost of replacing Plastic on a Polytunnel occasionally. Considerable amount of work to take down ... and put back up ... but I wanted a structure to extend the Start/End of my growing season. I didn't really consider a Polytunnel ... but after watching/reading Bruce's thoughts I'm not sure that Glass / Plastic tunnel is much different in terms of Ecological Impact.
Where hail is an issue, glass will NOT last forever, and sifting broken glass out of your garden bed is a daunting proposition. U V stabilized twin wall plastic will resist hail fairly well. (Greenhouses sometimes put up netting OVER their buildings to catch large hail. Here hail can be the size of a golf ball. Expect weather emergencies!) The sun-heated pit can work provided the right kind of soil and patterns of water flow through the soil around and above the pit. (I never tried it, but it's based on Plains Indian Kivas.)
I have been thinking about closed loop sustainability a lot, and the challenges our species faces into the future, and the limited resources future people will be left with. This was an interesting video to keep me thinking, lol!
Glad my video has helped with your thinking !
one thing to consider is most plastics are made from byproducts or essentially waste from refining crude into things like gasoline, diesel, etc. If it's not made into plastic, which essentially fixes the carbon for long periods, it'll be burned off.
That is a really good point. Thanks for bringing it up. So long as we have a demand for petrol/diesel we will have really cheap and ubiquitous plastics, as they need to make the most of the byproducts.
Could you do a comparison to just doing by raw cost? in other words, the total cost of setting up the tunnel and producing the vegetables in the poly tunnel vs. the total cost of purchasing the same type and amount of vegetables in a grocery store? How close would that approximate your calculations?
That would be an interesting comparison. One limitation is that I don't buy vegetables, so don't know the prices of anything. And woful it be better to compare to the price of crap sold in many supermarkets, or to local grown vegetables sold at farmers markets - or both? As a very broad point of comparison, I can easily grow 1000kg of mixed high value vegetables in a single season in this polytunnel. It cost me about €2500 to buy (not counting labour putting it up), so if the average price of vegetables is €2.50 per kg (I seriously don't know if this is in any way accurate!!!), then the value of veg in the first season would approximately equal the cost of the polytunnel. Market gardeners around here tell me that the polytunnel pays for itself in the first season. That doesn't include the labour of managing the tunnel though.
Another brilliant video, thank you!
Glad you liked it!
If you align the tunnels east-west and replace the north side with a scavenged wood wall covered with a reflective sheet of aluminum (doable with 'scales' from cans btw) you can increase the growth season of the tunnel, reduce the carbon cost of both plastic and metal, reduce loss due to damage and by placing the composting on the other side of the wall you can gather the waste heat of composting into the tunnel.
Baseline CO2 release isn't actually a worry for climate since an even increase in global temperature doesn't actually change *climate* it just slightly warms everything. It's the yearly cyclical mass release in the northern hemisphere through winter that causes much of the issues that, as of yet, haven't even been proven to exist.
Rule of thumb is simply conserve, ignore the CO2 cost of things and make everything last through cautious use and using readily available materials to replace materials you don't actually need.
Calculating your CO2 emission of the tunnel is, sadly, comical compared to your use of inefficient composting's CO2 and Methane releases.
I disagree with your point about increasing temperatures not changing climate, and there is increasing evidence about this. And I disagree with your other points about the carbon cycle.
I am concerned about the release of methane from my composting systems, but not with the release of CO2, as that is part of the living cycle of carbon. I am concerned about how my actions are causing fossil carbon to be released in to the atmosphere, which is why I did those calculations.
Hey Bruce a very enjoyable concept on the break down of pro and con cost of a poly tunnel....also agree that plastics are used too liberal on packaging for example in everyday life amenities and how Willy nilly it's just discarded without a second thought mainly down to an ignorance in society and also the arrogance of the magpie effect of having new and shiny things and not the so called ugly recycled look.....all the best 🇮🇪🇮🇪🇮🇪
Thanks. I agree completely with you. I figure that if we are worried about plastic - and we should be - we should be eliminating most of that mindless and frivolous uses long before we start to question the use in producing local food!
Hello , could you tell us the cost ,size you went for and suppliers of your poly tunnel - you said your poly came from Italy and your frame structure came from the U.K.
Just grow some trees for each plastic you buy to offset the CO2
We need to plant loads of trees already, and reduce what we use. I'm not convinced by the 'offset' process.
Also composting all that we can of course. I appreciate hearing all these calculations about the expense and think it is all important to consider.
@@REDGardens You definitely need trees as protection from the northerlies , perennial hedgerows to reduce pest pressure and creating resource. Nothing should have a single purpose. consider starting a tree nursery for that end.
@@danielallouche2493 I am definitely planning some trees as protection from the wind, but not sure I have the capacity for a nursery just yet.
@@REDGardensruclips.net/video/NF-5IHMjI6M/видео.html . This is a simple way to start
Uau man, jobs increíble. Congratulations friend
Thanks
I only made it 1/2 way through this video as this topic is so vague. I do everything by the cost, in doing so I presume the cost covers whatever it needs to so all can profit.
I do have a question about how you grow your tomatoes. Do you use the standard way most homeowners use, or do you use the industrial way, where you roll the tops up to get new growth at the bottom and new tomatoes?
I wish we could use the cost method you suggest. Unfortunately I have found that so often the cheaper option is the more environmentally destructive.
I grow tomatoes a fairly conversional way.
They are able to recycle the black plastic used to bale hat, these are made into bin bags, so you never know there may actually be a way to recycle the plastic on your greenhouse, but it would need a specialist
There are lots of different recycling options, though for this analysis, I decided to take the worst case scenario from an emissions standpoint, with incineration. Recycling would make a the option even better.
Incredible video. Thanks for your thorough research and scientific approach. I so commend you for correcting many of the climate denial claims and misconceptions in the comments!!
Thanks for that!
you're a gem. you are my inspiration to grow my own food
Fantastic video.
Thanks.
I'm assuming that there would be a fairly significant saving in CO2 in reduced water usage and other areas too.
Actually, the supply of water in our village has a very low climate cost, with lots of rain and a big aquifer not so far under ground. So I think it's impact would be negligible
@@REDGardens in respect to most others connected to municipal supplies it might... Plus groundwater reduction isn't an entirely bad thing :)
I have been thinking on this exact same problem. But I'm in Kentucky. So the validity of a simple in ground garden should be better.
That makes sense. So much depends on context.
Thanks for this discussion. I suppose, the production of glass for a greenhouse uses a lot of energy too, so the comparison won't be too bad for the plastic.
I just did a bit of research (as I was interested in the numbers myself) and apparently in the production of 1kg of glass there would be 1.2kg CO2e emissions. less per kg that plastic, but glass is a lot heavier - about 7.5 kg/m2 or 9kg CO2e/m2. If I built a glasshouse the same size, rather than a polytunnel, I estimated that the area of glass would be about 220m2. So 220 x 9 = 1980 kg CO2e to manufacture the glass compared with 420 kg for the plastic (including incineration). So glass has almost 5 times the emissions, but hopefully would last more than 5 times longer than plastic, without the end of life issues, brother pollution problems. But then the structure would need to be a lot stronger and more rigid, and that would be another calculation!
Is your water from your own spring or processed locally? I had this same concern about polytunnels. I keep late frosts away from my young veg by using under floor covering that had been out in a skip. A local farmer asked me what I was doing...
Birdy
Thank you for an interesting analysis. I've run some numbers about lettuce transport in the US. As you know, 90% of our lettuce is grown on the California/Arizona border, and it gets transported as far as 5000 km away via diesel-burning trucks. As lettuce can be grown in any climate for much of the year here, this is the very definition of insanity, don't you think? I computed it in terms of calories spent to get a 70-calorie head of Iceberg lettuce (inexplicably, our favorite) to the east coast, of which typically I'd guess only half gets eaten before it turns brown and people throw it away into plastic waste bags that then go into landfill. The result was much head-banging on my part. Public policy plus consumer education could fix this. It does not.
Your point about the food waste is a really important one, and something that is not normally taken into consideration. I often stress that when the food that I produce doesn't get eaten, it is fine, as it just ends up being composted to make more food next year. But this is only because there are so little resources going into the growing of this food, compared to almost everything you can buy in the shops.
Nice video thank you.
If your worrying about the cost work your green house harder. I see green house not being used when its too hot or to cold. But if you door lets a tractor in a greenhouse can dry firewood , sundry apples and tomatoes, house the chickens cover the swingset even dry clothes.
Yes, you are right. We should be able to use these things much more often. Thankfully in Ireland it rarely gets too hot or too cold to grow something.
I avoid plastic in my garden like the plague, but that's mostly random pieces of trash bag and the like that might end up buried in the soil. I'm not above using PVC tubing for stakes, PEX tubing for low hoops, or sheeting to cover the hoops. If I had the room and the money, I'd love to have a poly tunnel like yours. Like you, I somewhat offset my carbon footprint by composting green & brown materials, and making bio-char to use in the veggie garden.
I recycle household plastics & metal, and shred what I can of incoming paper mail to use as mulch. For larger mulching jobs, I lay down sheet cardboard and cover with leaves. At times, one person's efforts may feel meager, but we can all play a roll in improving this global environment. Thanks for doing your part.
I have learned the hard way that any miscellaneous plastic in the garden eventually ends up in the soil, unless I am very careful with it.
Biochar is a possibility for sequestering, and I want to crunch a few numbers about the effectiveness of it at a small scale in the future. Other sources of carbon in the compost and soils seem to really depend on continued care for them to remain sequestered.
@@REDGardens, Your response prompted me to ask myself 2 questions related to two of my practices. I stockpile loads of fall leaves, which I then use to rebuild my compost pile the following year, by mixing them with green materials. I also make biochar, which I inoculate by mixing it into my compost pile. Questions: One, do rotting leaves emit CO2, and two, is biochar stable? The simple answers are yes & yes. Keep in mind that I don't hold a college degree, and I'm not an expert at anything, though I'm fairly proficient at procrastination. I learn by asking questions, then go looking for answers. Sorting through the data is where patience and rational thought come into play. I muddle through!
Admittedly, I'm not saving a very big piece of the planet, and maybe the best I can hope for is to improve the soil in my garden, grow some nutritious veggies to share, and pass on some useful gardening tips to others. So far, my efforts provide mild pleasure & contentment.
Just as a side note, I think if we keep consuming natural resources and polluting the environment, we as a species may have to revert to a agrarian society. Numerous hamlets around the globe, focused largely on producing only what they need for their own survival. I can think of worse outcomes.
Appreciate what you're doing in Ireland.
news.mit.edu/2012/leaf-decay-1004
en.wikipedia.org/wiki/Biochar
en.wikipedia.org/wiki/Agrarian_society
@@brianwhite9555 I compost leaves, but don't mix them with anything. They are in their own, separate, heap and take at least a year to break down, maybe two. The resulting "leafmould" stimulates mycorrhizal fungi growth, so when used at planting help the new plants establish - and I reckon works better than expensive mycorrhizal fungi packets that I have bought in the past :). Yes rotting leaves release CO2, but it is the same CO2 that those leaves absorbed during the year, and the new leaves will absorb in the coming year, therefore "sustainable" ... or so I have persuaded myself :)
@@kgarden8960, Thanks for giving me a huge laugh, my ribs still hurt. I loved how you validated your own theory on CO2 absorption, "sustainable ... or so I have persuaded myself." That sounds like something I would say, quite tongue-in-cheek. :)
What's your location? I'm in SE Michigan, USA. What type of leaves are you composting? Although I have direct access to loads of oak leaves in the fall, I avoid them. Unless they're shredded, they seem to take too long to break down. I prefer a softer leaf, such as maple & the like, and just one neighbor provides me with all the leaves I need for one season. I'm able to thoroughly mulch my open areas & raised beds in the fall, plus densely pack two leaf bins that are approximately 4'H x 5'L x 4'D. I don't tarp the leaf bins, and the leaves sit for a good 7 months before I start feeding them to the compost pile in early summer, right after I've taken as much finished compost from the pile as I need for spring plantings. I need the stockpiled leaves to balance out all the fresh grass clippings that same neighbor supplies me with all summer. My composting area is approximately 6' x 8', and completely open, no walls. It's literally a pile that I continually add to all through the growing season, closing it out by the middle of November at the latest. It sits until mid May of the following year, when I run my tiller through it a couple of times before starting to use the finished compost for plantings. This system works well for me, but may not be convenient for all gardeners.
Through the season, as I dig deeper into the leaf bins, I find that the leaves have turned into the fine leaf mold(American spelling) that you referenced.
I do apply this as a mulch around many of my plantings. Honestly, I love creating compost & leaf mold as much as I love growing veggies.
Mother Nature is a Grand Old Dame!
@@brianwhite9555 I'm in UK, East Anglia - the bit that sticks out on the right, level with London :) Agree Oak leaves are tougher, and allelopathic (but I suspect any inhibiting effect would break down within 12 months). Some people "collect" them using a rotary mower with collector, that chops up the leaves and speeds rotting - the pile is smaller / more dense too. I just chuck all mine in a pile with netting to stop the wind putting them back again ... its about 8' x 8' and starts off 4' high. By Summer it has shrunk by half and I re-pile it up at the back and then before leaf-fall I move that pile to a fresh heap alongside, leaving the bin empty / ready. Yours will have gone into your Summer compost heap instead and I understand your use to have Brown material to go with the Green lawn clippings ... I'm about to buy a Robot Mower, and won't have any more grass collection ... nor sit-no-the-mower-duty ... so that's my solution to that problem, but it is going to stop me getting through my Podcast backlog :) I don't suppose you also grow in a greenhouse? I replace the soil annually in mine, and I put my compost heap in there, its a bit rough at that stage, but the Tomato etc. plants don't mind. When I take it out at the end of the season it is beautifully fine, and perfected suitable for potting / planting etc.
what is the cost to build the same size greenhouse built out of lumber and glass to that of plastic and metal, I don't really see this as a worse option as there are recyclable options with plastics.
I don't know the difference, but would imagine it to be at least 5 times the price.
I would wonder if the effects of the contribution of micro plastics have been considered? I have been hesitating to go buy into using plastic for this reason.
I have thought about that, but it seems that most micro plastics are due to clothing and fabric, or where pieces of plastic are bashed together in the ocean. In the garden there is definitely an issue with plastic bags, like bags for compost, that are not UV stabilised, as they can really shred and disintegrate after a few years. With this polytunnel plastic I am not sure what physical mechanism woful produce micro plastics. Perhaps constantly scratching it.
I only use plastic sheeting to cover selected crops to overwinter. Cabbage etc.
My guess is that while the plastic may last 7 years, it will become more opaque over time, and less efficient in transmitting light.
I was wondering if the Polytunnel allows you to grow seedlings for elsewhere in your garden. If so, that may offset the costs of transporting seedlings that were commercially produced.
Cody's Lab did an experiment using plastic tanks to grow plants. His experiments were focused on heightened CO² levels in a sealed enviroment, but he did discuss light transmission, and even in the thick walled, dyed plastic tanks there was surprisingly little reduction in light levels. Still well above what the plants required to grow. Just because the plastic isn't optically clear doesn't mean it is keeping out light. It's just getting diffused
Great perspective given on the ecological effects
Thanks.
Would a polycarbonate one be better? More expensive but they seem to last much longer. Someone in my family has one and it is decades old and still going strong.
I don’t have any experience with them, but I hear that they can be quite good at last a long time.
Realistically the steel frame should hold even more than 20 years. Shouldn't it?
Have you considered the cost/benefits of a glass house? They are obviously very expensive in the setup (especially considering the engineering to keep them cool in summer, with (auto-) opening (roof-)windows) but then should work for a long time...
Yes, the steel frame should last a lot longer, but I wanted to be conservative with my calculations. I haven't done a cost/benefit analysis of a glass house yet, but I agree that in the long run it will likely be better.
More and more renewable energy will be used by factories and EV trucks, so the CO2 emissions related to those plastic and steel will be much less in the near future.
Hopefully. It would also be great to see the plastic sheeting made from biomass.
how is it that 1 kg of plastic releases 3 kg of Co2 when burned? That math does not add up.
Sorry, I should have included the calculation. Essentially it is because the carbon only makes up about 27% of the weight of the carbon dioxide (one atom of Carbon has an atomic mass of 12 + two atoms of Oxygen with an atomic mass of 16 each = a CO2 molecule with a mass of 44 ... 12 / 44 = 27%)
The carbon makes up about 86% of the weight go the plastic (C2H4).
So burning 1 kg of plastic releases 0.86 kg of pre carbon, but this is combined with oxygen (the actual burning process) to produce 0.86 divided by 27% = about 3.2 kg of CO2 gas - it is a bit confusing, but greenhouse gasses are measured in CO2 equivalent, not the carbon. Hope that makes sense.
Excellent video, would mind Which company produced this kinds of Polytunnel
I bought this polytunnel from polydome.ie
What tunnel is that? Who makes it? How are the ribs secure to the ground?
I get it from Polydome.ie - their 5.5m wide model
There are posts in the ground embedded in a bit of concrete, keeping the structure up and in place, and the edge of the plastic is burred in the ground to keep it all tight and prevent it from blowing away.
I'd be interested in your take on collecting rain water and using a solar powered pump. Depending on how your catchment is set up (possibly from tour polytunnel?) This would be interesting due to minimizing use of ground or tap water. I thought about collecting water from one part of my house this year, but didn't get to it early enough and our rainy season is about over.
I always enjoy your content, and tour perspective.!
Collecting rainwater is a great option, especially if you have a polytunnel. But it is something I have not got around to doing yet - hopefully this season. it is not such a big issue where I am located as we have a lot of easily accessible and clean ground water.
The jury is still out on whether or not the carbon cost to manufacturing and delivering solar panels outweighs the carbon benefit they provide. A lot of former renewable energy advocates have backed far off of their support for them, not only for that reason, but because the storage of excess power they or wind provide (as a primary source of power for millions at a time) is a problem we are years from solving--and all the solutions require a lot of fossil fuel to implement. Frustrating, I know, but there really is no magic energy solution out there yet.
I agree, we should be much more mindful of our relationship with the planet with which, not on which, we live. Sure, we should move toward fewer carbon emissions, but learning to live with nature, not apart from it, is the greater benefit. Perhaps sooner, more than later, we can eliminate the use of plastics. In that process, we can eliminate the use of frivolous and unnecessary plastics first. Then, by learning to eat more locally and less globally, we can move in a more earth-friendly direction. This applies not only to where and how we grow the food we need, but also into areas such as building material, transportation methods and clothing fibers. Moreover, this issue goes to such issues as attitudes, human cultures, the arts and what we envision as what it means to be human, what it means to be a part of a community, a culture, a climate, a plant. For quite some time, perhaps tens of thousands of years, humans have seen the plant (world) as an enemy that brings death (bad/evil). However, homo sapiens have seldom if ever been on any endangered species list and if we are to better than the critters, the bugs, the viruses, the bacteria, the birds, fish and animals, perhaps what shall make us better is that we become able to care for their survival as much as we concern ourselves with our own comforts.
Well said.
I've noticed that the first polytunnel shown in this video has high sides, I would like one like this, can you recommend a supplier?
I got it from polydome.ie
Plastic needs to be looked at completely differently by society as whole. I started composting 1m sq bins. 6 in total started hot boxing few months back and at its worst im pulling half a bucket of plastic and bits out of 1m2. This stuff lasts forever. I find orange plastic twine rope which was used by prevoius owner of house over 12 YEARS ago. Plastic needs addressing as a high contaminant. Im a sparky and i spend days cutting holes in PVC electrical thibgs so not free of guilt here and trying not to preach but it is scary when you think of the micro scale
Yes! Plastic in the compost is a much more serious issue.
The plants grown underneath the polytunnel - how much carbon will they utilize from the air?
They will absorb quite a bit. It would be interesting to estimate how much. But most of it will be released back into the atmosphere when we eat the food or the plants decompose.
I am not sure how you calculated the co2 for steel production. Steel is extensively recycled in the uk rather than made from ore. This is a major saving in CO2.
Good point. In this video I wanted to assume a worst case scenario, but now that I think of it the figures I used may have been for total steel production, which I may have incorporated a typical proportion of recycled steel.
Great video and calculations! Thanks for sharing them!!
Thanks.
Excellent work. Thank you for sharing.
Thanks
How do you hold the plastic to the lumber. I tried staples but they dont hold like I need them to
The plastic is fixed to the timber posts by rolling up a piece of wood (1x2) in the plastic a few times and screwing this to the post.
nice video
Very useful .Thank you for the video, the post-production and the ideas!!! Absolutely brilliant explanations. From my point of view, Carbon is not the problem ! how politics use the "carbon" that is the problem. Vegetables use that carbon to take breath for instance if I remeber the clasess of biology at highschool. There are many elements too much dangerous for the " planet" what CO2 is, gases flurorcarbonados, metals as cobalt in the soil, NOx in the air... However use these practises to cultivate free of quimicals and re-using all we can, they seem for myself a great idea, but is not far away the ways our granparents used to do.( mine reusing all they have, all he activities they do are a close chain). My question is, Why I have to buy an electric car- i s not the goverments are really interested in it becouse of all the benefits they earn. I listen a couple weeks ago what grow a family is a enviroment crime!! why I have to buy a new washer ever three years , pay an extra money for a bag to carry all the foods they are wrapped in the mall in plastic, or pay new ECO taxes for the "planet"? Probably I havent the truth of all of that, anyway many thanks for all ( I am a fan of this chanel, sorry for my english is not very good)
Thanks, glad you like my video!
I disagree with you about carbon. Rising CO2 levels in the atmosphere is absolutely a problem, and that problem will only get worse. The fact that there are a lot of messed up and contradictory issues relating to all the ‘eco’ stuff, and a huge amount of manipulation, misinformation and lack of understanding, does not diminish this critical issue.
How do you only have 18K subs?
That is something I don't know!
And now it's 50k+
18k is still huge though, 18'000 people,
Your videos are always packed with useful and interesting information. Thanks for sharing!
Glad you appreciate them!
Aren't your transport numbers flawed because they aren't transporting one sheet of plastic/crate of vegetables to Ireland, but a whole truck load of items to Ireland, effectively splitting the carbon between all items on the truck? Thanks for sharing, I really enjoy your content.
I think the transport numbers are correct as they are grams of CO2 per tonne of material per km. They are apparently considering a typical loading and truck configuration, and typical road system. the truck no doubt will be full coming to Ireland, and likely the polytunnel supplier that I used just up the road would be buying in by the full truck load. So the full truck could be hauling about 20 tonnes (just an estimate) and traveling 3000 km, so the total emissions wound be 0.15kg x 3000km x 20 tonne = 9000kg CO2 emissions. Of which 31.5kg is for the part of a roll that I received, and the rest is for the rest of the material being hauled. If it was just hauling the plastic for me, with an otherwise empty load, then the emission would be way higher to account for the weight of the truck. But I can only assume typical or average figures supplied by this who research this kind of stuff. Or am I understanding your question correctly?
Thank you very much. That was excellent.
Glad you appreciated it.
Awesome!
:)
Is there a polytunnel you can recommend? Which one do you have?
I am not sure I can recommend any plolytunnel, as I have only used the ones from polydome.ie - but they seem good.
good numbercrunching there. You're doing well. And besides all o that; in Spain they also use greenhouses, albeit they are in use longer periods each year. keep up the great work! (must check this patronage thing once more, saw on my paypal that there wasn't any money written of to you last months. Sorry about that) Greetings
Thanks. Yeah, there is so much plastic and other resources used pretty much everywhere food is produced. Thanks for the patreon thing!
Thank you for your workings on the dynamics of growing under plastic. What would be the 'cost' of c02 in a glass house with a wooden frame? What would be the monetary cost of relocating to a climate where food that one wishes to eat can be grown without plastic, glass and steel? The cost to the countries now growing foods that would not be able to grow what they want and send it over? Just bullet points my friend, not jibes at your good self! Because for me, the idea that I (or anyone) should feel guilty for their/my actions which try and eliminate the NEED for another's input is not outweighed by THEIR desire to send and make available their products or produce! Thanks.
Good questions/observations.
I don't have any figures about the C)2 cost of a glasshouse, but i know that glass has a lot more embedded energy in it than plastic, but it can last a lot longer (and is better to grow under). the other issue is that the structure needs to be a lot more rigid in a glasshouse, so more material needed. it would be an interesting exercise, and no doubt someone has done it.
For me, one should adapt to what you can produce in your area. The issue with a greenhouse is that it dramatically improves productivity, choice, reliability and enables me to eat fresh food all year round - with relatively little infrastructure.
The research that I have done has led me to see that the global food supply system is so morally and ecologically corrupt/bankrupt that the person on the ground growing food is going to get screwed ALL the time. It is the middle men and companies that control everything and extract all the wealth and have all the power/control. Well not everywhere, and in every circumstance, but it is extremely hard to avoid. The whole system needs to change in my opinion, and I am not going to stop growing my own food, and encouraging others to do the same, in hopes that some farmer on the other end of the money/power chain gets a few extra crumbs for their hard work. In many/most cases they are being controlled so that others can make money selling things to me and you, and using huge amounts of non renewable resources in the process. If you could establish direct relationships with the farmers, to ship direct from them to your community, then that is another thing (and we have been exploring that in our community).
@@REDGardens thank you for that full-on reply. See you next time.
What if they were transporting two polytunnels..or 50?
The figures I used were from typical loading of transport trucks, which I assume account for what the average loading is. So the figures already include the fact that the truck was full.
Probably a greenhouse with glass panels will be more ecological alternative, never done the calculations ofc lol. More metal will go into making one but the glass on the other hand is not as problematic as plastic i believe
I have the same thoughts, especially if the glass lasts so much longer. The steel frame would definitely need to be stronger and more rigid, needing more metal, as well as a lot more joints, fixings, seals and other materials. It would be very interesting to do those full calculations. I suspect it will come down to a the perception or weighting of different ecological issues, i.e. carbon emissions vs plastic waste, which are not easy to compare. And if the plastic is incinerated in the end and part of the embedded energy is used for energy production then that would really change things, I suspect.
@@REDGardens the main benefit I think is that glass after all is melted sand, the negative effect of producing glass might be bigger than producing the amount of plastic but when we retire glass it has less to none negative impact on nature. Plus i think glass is 100% recicable. Much more fire resistant as well
Hi, I want to buy a polytunnel. Can you recommend one good quality that I won't have to change for 5-10 years. I am looking for upto 3 wide and 6m long max. Thank you so much x
Why does this sound so similar to the solar and lithium battery situation for homeowners?
So the debacle of at East Anglia means nothing?
Yep, that was a storm in a teacup, from 20 years ago. A hell of a lot has happened since then! And those involved have been completely cleared of any wrong doing by pretty much every agency and organisation that has looked into the matter. Except of course those who continue to cling to this red herring in a desperate attempt to prevent any action on climate change that might hurt their profits. Such old, old news, I am surprised it is still a thing!
www.ucsusa.org/global-warming/solutions/fight-misinformation/debunking-misinformation-stolen-emails-climategate.html
solid work, thank you for this
Thanks, glad you appreciate it.
co2 is not a polutant ,we are in a co2 drought only 450ppm the optimum is 1000ppm for plant growth hence why commercial growers pump it into their grow spaces
Although it would be lovely and reassuring if that was the full story (and true), but unfortunately the world is a lot more complex than that.
@@REDGardens exactly ,global warming is a corperate scam ,all predictions and models have proven to be poor and wrong over and over again
Ummm, wrong again.
Looks great. I want one of these. What part of Ireland?
I am based in North Tipperary.
What micron and gauge is the cover your using please thanks
It is apparently a 900 gauge plastic.
Thanks @@REDGardens
the biggest issue for me is the use of seeds and plants that are not adapted to the local ecology. So tomatoes, in my opinion, are a Mediterranean plant. Kale would do better in a northern latitude. The further we get from local food, the more stuff we have to do to trick the seasons by extension and other means. Ireland would be great for potatoes, i think but for eggplant, Italy might be a better ecology. Does that imply that only we should eat what we can grow unassisted? No, but if you need a polytunnel to grow it, it probably isn't adapted to your region.
that is a good way of putting it, and yes it would be good to adapt to things that grow easily in our ecology/region.
I find the benefits of a polytunnel here in Ireland to be a lot more than being able to grow food that is not adapted to ou climate (as much as I love tomatoes). It also increases the yield of what you can produce, especially in the spring and autumn, so is really useful when available land is limited. It also means that the plants are less likely to be damaged from storms or other unusual weather events. So while growing and eating what is adapted to this locality has definite benefits, the polytunnel like this can be both a stepping stone for people to adapt their diet, extend the amount of the season where local food is available, and increase the resilience of those crops in some situations. But as you say, that approach takes extra work and resources, so there is always a tradeoff.
@@REDGardens I like the way you think. Who can live without tomatoes? And if the choice is a polytunnel vs. no tomatoes or store bought bland ones...I'd do the polytunnel. I have been using low tunnels and they're nice too. Much cheaper to put up and with steel bent pipe very sturdy too. Have you tried wheat in the polytunnel? That's a calorie and compost crop with decent root systems.
@@jeffdustin I am planning to explore the use of low tunnels some more, as I think they could be a very useful option. I haven't tried wheat in a polytunnel, but it would be interesting to explore a small patch to see how it grows.
@@REDGardens The green manure could do double duty as a calorie and compost crop per Grow Biointensive style farming. You get to eat and also create a lot of mass for the compost pile or bin. Grain seems to prefer dry and hot climates so the polytunnel might be a good marriage of the two. Plus I know wheat can lodge or fall over. Maybe the polytunnel would protect the wheat to some extent? Sorry to talk your ear off!
@@jeffdustin Yeah, it would be interesting to see what growing wheat would be like in the polytuunel as a dual crop/compost. One issue I can see is that you would have to wait until the what is ready before you could plant any other crop, so the timing may not work for some crops you want to grew. The people have mentioned crops like field beans where they harvest the tops as a type of spinach throughout the growth cycle, and in this way they can get a yield and a compost crop that they can pull up whenever it is needed.
ahaha here in brazil i am far ahead of you,i used old plastic from tomato growers that would go to the trash and made my greenhouse and 2 more for my dad and mom hourses
Excellent!
The real problem is, that it doesn't really of setts the carbon footprint of producing and shipping the food from Spain, because of the scale economics of supply system. The food that is currently produced in Spain would be produced anyways, as every producer in capitalist system maximizes the food production. If the demand in UK becomes lower, they simply lower the price to sell it cheaper to other markets and make profit. Also EU is subsidizing agriculture heavily, so it's easier to get away with wasting resources. When the economy is not tied to resources, but to fiat money supply, the waste will be always the preferential option.
You make some very interesting and important points. It is so important to recognise that there are larger pressures at work out there. In ways it is similar to the deciding to not fly in order to save CO2 emissions, but the airplane flies anyway, and someone else likely got the seat you would have taken, only at a cheaper price. In this world it is hard to see how to make an impact, especially with the Jevons paradox and rebound effect.
But I see it in other ways as well, which is both small personal scale and playing the 'long game'.
One of the reasons for making the video was to provide some perspective to counter the common argument that all plastic is bad, which seems to be preventing a lot of people from using a polytunnel, which according to my calculations would use less fossil fuels in the long run than shipping the food from elsewhere. One individuals choice to buy a polytunnel may not have any impact on the bigger issues, as you detail, but at least they will be growing more of their own food, which has huge benefits at a local and personal level.
In dealing with the larger systems, I am playing the long game, where I am trying to seed ideas and ways of thinking that will hopefully have an effect in years to come. The way I see it, the more people who grow food for themselves here in Ireland, with or without the help of the protected cropping of polytunnels, the fewer trucks will be coming into the country carrying vegetables from Spain, and that is a good thing. If the food isn't being purchased, it doesn't make sense to truck it all the way here. But I recognise that we are talking thousands of people growing lots of their own food to make any real difference to the transport part of the equation - who knows what will happen at the production side of things.
Another aspect of this long game is to try to shift attitudes about our food supply systems in general, and to open up ideas and possibilities to counter the large scale agricultural systems. Perhaps that will eventually lead to changes in policy at national and EU levels - but I am not too hopeful about that.
The other part of all of this, which I didn't go into at all, is that many of the large scale systems of energy, resources, subsidies, debt, economic growth, etc. on which the current capitalist production system depends, seem to be a lot less resilient going into the future, and I think we need to establish different food systems to transition to. But that is a whole other discussion.
@@REDGardens Thank you for your detailed reply. Don't get me wrong, I admire what you do. I was just trying to play a devil's advocate here a little bit. I think that we should undermine the system no matter how little the impact. Although I have no hope for the future, it's a matter of a principle not to go into the night quietly.
pafnucek a Devil’s advocate is an important role. Your comment got me to think quite a bit more about it all, and I took the opportunity to get a few thoughts down in replying. All part of the process. So thanks for that!
Don’t go into the night quietly!
the problem with plastic is PACKAGING, not with tools usage.
nice work!
Glad you appreciate it.
Excellent. Valuable info. Thank you. Plus, there is the aspect of the unhealthy effect on us of contact with plastic. And the unhealthy effect of the extraction of the raw materials on the ecosystem, and the cost in wars over those resources, and the unhealthy aspects of the processing of the plastic. And the unhealthy effects on workers at every step of the extraction and manufacture process.
Yes, there is a lot of really unhealthy issues out there. That is why I try to localise it all, and take responsibility for as much as I can, rather than pass those issues on to others.
Growing food for yourself is much better than buying it at the grocery store let alone fast food
It is tough to go back, once you get used to eating your own grown vegetables.
Great info. What caused the fire?
The adjacent compost station burned down - I made a video about it all ruclips.net/video/4Jl53PZPsdU/видео.html
Is it hybrid seeds ?
I use a few hybrid seeds for some crops, but mostly plant open pollinated seeds
I like your thoughtfulness and details though I feel that the justification is still hard to swallow and plastic in the garden to me, is anethema. How do we factor in and account for people who lose their farm to fracking, habitiat loss due to pipeline and fracking infrastructure that pollutes, displaces, sickens, and kills biota and people? The petros don't have a fund for those harmed by their profit taking venture. It's not as though an endangered species has a bank account. How is it that we can come to these conclusions without widening the scope of our inquiry to the harm being done to all those down stream of petro extraction? Just me, out here, pondering, procrastinating, and philosophizing. At least you are getting things done. And that is a very good thing indeed!
Those are all very important points. My approach is to try to take as much control and responsibility as I can for the food supply system for myself and my community, so that these issues are not externalised or passed on to others. I think it would be impossible to get food from elsewhere that didn't involve the use of more plastic, and most cases a hell of a lot more plastic, that what I can produce in this polytunnel. Not prefect, and still problematic, but a lot better than other options at the moment.