Easiest Way to Use Neem Oil | The Problems with Spraying | Neem Oil Root/Soil Drench
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- Опубликовано: 30 июл 2024
- Hi folks, welcome to a quick update on how I like to use neem oil on the allotment. You can see last year's video here:
• (Almost) Everything yo...
Really hope you enjoy this one.
Neem Oil Links:
kit.co/NaturallyJB/neem-oil-p...
Support the channel:
If you enjoyed this video and want to donate to help me keep making them you can do so at: / natjb or make one-off donations through ko-fi.com/naturallyjb or at paypal.me/naturallyjb. Thank you so much for considering this, times are hard and there is no pressure!
Additional notes:
1. The legal situation for using Neem Oil / Azadirachtin is quite complex. I might do a separate video on this at a later date if people wish for it.
Neem oil isn't technically a registered / approved pesticide in the UK. It is approved in the EU under EC Reg 1107/2209 (sitem.herts.ac.uk/aeru/bpdb/R.... There are numerous research documents discussing its effects and impacts, which conclude that by and large, it is safe. A good summary can be found in this document produced by the US Environmental Protection Agency: www3.epa.gov/pesticides/chem_...
2. BUT Neem oil is NOT banned in the UK. This is a rumour that was started by someone editing the wikipedia page for neem oil and getting a few details wrong. Because the active ingredient isn't technically approved for pesticidal use alone, it is necessary for products containing the active ingredient to go through a process of individual approval. There are examples of products containing azadirachtin which have been approved for the UK market. More info here:
(webarchive.nationalarchives.g...) Using the mixture as I describe in the video is considered a home remedy and using it at a small scale is likely permissible under UK law in the same way that many other home made garden remedies such as garlic sprays, compost tea, spraying milk for mildew etc. are allowed.
More info here: www.hse.gov.uk/pesticides/use...
3. Neem oil absolutely stinks so be careful using it indoors or in greenhouses and try to avoid getting it on yourself or your clothes!
4. Neem oil can be really effective for potted plants, by making up a solution in the same way that I've shown in part 4, and using it to water the plant.
5. Neem oil solidifies in cold temperatures and can be harmed by high temperatures. If you need to liquefy solidified oil then place the bottle in warm, but NOT HOT, water.
Follow me on Instagram if you want, although I’m bad at posting:
/ naturally_jb
Timestamps:
00:00 - Introduction
00:35 - Neem Oil Application Methods
04:15 - Easiest Neem Oil Mixture
04:59 - Mixture Recipe
06:30 - Soil / Root Drench Method
Easiest Way to Use Neem Oil | Issues with Spraying | Neem Oil Root Soil Drench
![The BEST Fungus Gnat Killer [Actually Works!] 5 Yrs Gnat-Free and Counting!](/img/1.gif)
I have a big, old purple elder which has been badly infested with black fly for the last 2 seasons. The honeydew they generate has absolutely hammered everything growing below the elder. In desperation, I applied 3 lots of the neem oil drench during April and May. 40 litres each time. To my surprise and delight - it worked. The elder is completely bug free and the plants growing beneath it are flowering their hearts out. A brilliant piece of advice for which many, many thanks.
Really glad to hear it, well done!
I think the idea behind spraying the leaves is that the soap will suffocate some of the pests immediately, but a root drench will really drive it home
I watched your previous video, and appreciate the update! You explained it really thoroughly, and addressed all of my concerns! Thank you!
You did it! One more update… off your plate! Thank you for your video! You “are” a natural thoughtful conscientious teacher. I liked hearing your ‘perspective’ on the ‘drench’ as opposed to the continuing to spray, when that didn’t seem right/as productive anymore. And yes… to give up that messy sprayer… for a bamboo stick - brilliant! That… is intuition at work! Carry on! 😌
Thank you so much!
Thanks, what a great way to get out in front of the problem
This is an ancient Indian method. Using neem oil, neem cake, etc to take care of many pests and diseases.
❤I really enjoyed the video I have been looking for organic method spray 😂😂
Will this work to get rid of the fungus gnats I have.
Can't wait to try this. Aphids are terrible here.
Commenting for viewer engagement, liked and subscribed. Woohoo, trifecta! First-time channel viewer; regards from Kuala Lumpur
Thanks JB, I messaged you about neem oil and you sent me a link to this video, it's been such a help, really a whole lot easier than spraying like last year. Thanks.
As it not a contact spray watering in via the soul seems much more logical and straightforward.
Keep safe 👍
Your way of explaining things is fabulous. I got a lot out of this video. Thank you and hello from Quebec!
Ah thank you so much! Really glad you enjoyed
Thank you for this great tip. I am a newbie to Neam oil and this tip sounds so much easier than messing with a sprayer. Good video showing what the mixture should look like too.
May you have a booming pepper crop and a happy gardening season.
Thank you so much for sharing your precious experiences and useful information🙏🏼🕊☮️💚🙋🏻♀️
Others have commented as well but you can get neem in various forms. I add the neem cake to my beds in spring and early fall. I also use it as a tea on plants that are very susceptible to insect pressure at various times of the year. Neem is also a great fertilizer so top dressing with it is awesome.
I have stayed away from the oil because it’s too expensive for me.
Thanks you for the information I am having some problem with nematodes I was looking all over RUclips.i will try
This is a really useful video - you have such a knack of explaining stuff that people will find so clear and not patronising! Love it! ❤️ Also, I like that you’ve followed up on last year with your thoughts and changes in direction you’ve found from your experience. Top information video!
Ahh thank you so much Niall, that means a lot!
hi from the states! i *hate* spraying. you have given me hope. basically getting a lot of pest action on things i never did in FL like *rosemary* ! it's astounding and dismaying. and i'm supposed to be setting up a food garden but if even herbs are being attacked this hard................ anyway, thank you for this root drench method. i am going to try that and see if i can save everything from torment. (my sage is getting stripped too, it's unreal!).
truly - i mean it when i say i have hope now. i've been really just so low on all of this. pest management can be one of the hardest, most demoralizing parts of gardening. and here i thought that in GA it would be the deer. (i'm sure that will come into play as soon as i get the pest stuff sorted. -___- haha. ugh.) i'll be checking out more of your channel now! this was my first vid to come across.
what a soothing voice
I can help you there JB, I use the root drench on my raised bed and it seems to work nicely 😀
I’ll keep you updated if anything changes.
Oh really! I didn't know that! Sounds like it's keeping your plants pest free which is great to know!
@@JBNat so far so good. Using it on the bed with beans and the one with courgettes. Same as you, the smell is horrendous and it’s a nightmare if it’s on your leafy greens.
Hi JB. I'm impressed that you tried something but changed tack. It's a learning curve for all of us. Enjoy the week ahead, beautiful weather forecast. 😃
@@JBNat hi, when did u neem drench your raised beds? When you planted the plants? If not, how long did you wait? Thank u!
This is what I’ve been looking for!
Thanks for the info on neem oil it got rid of whitefly with one application
Thanks for the update!
years backed worked in greenhouses and we drenched with some ruff chemicals.....now trying to go organic for the last 20 yrs..... I have been looking for a fungicide drench for my cuttings...since being an organic fungicide, will it drench as one....great info.....finally found You....
Hi. I really like this method. Thank you.
Glad you enjoyed!
Hi JB, I have been scanning Google for about three days to find out exactly how to do the drench and here you were all the time. My search is over. Thank you so much and God bless you real big ✝️ 💚 🥀 🌿 🍅
Ah fantastic! I'm so glad it was helpful 😃
👍
I love this idea, thank you! 🙏🙏🙏💚💚💚🙋♀️🙋♀️🙋♀️
A informative and interesting video JB so I will have to get neem oil.
Thanks David! I really do recommend the stuff. Make sure to get 100% cold pressed. There's a few other products on the market but cold pressed has the highest azadirachtin content :) good luck!
Thanks. That’s very encouraging. I’ll be trying it later today, and probably spray as well, as my cabbages and cauliflowers are getting horribly deformed by aphid. Fingers crossed.
Good luck!
Been using neem oil once every two weeks to control asparagus beetle teaspoon of oil + 1/2 teaspoon fairy liquid in one litre spray . For 30 plants starting in June. Which work’s extremely well. But it’s a bit near my pond so will try the watering method .
I love this! I almost never use the sprayer because it's a total pest. I am going to give this a go. Thank you :-)
Thank you so much! I was really hoping people might get some use from this 😁
You can try looking into neem cake, which is the byproduct of making neem oil. They can be used as fertilizer with the added benefit of neem's chemicals.
I'm actually using that this year! Discuss it briefly in my potting up pepper video 😊
I love how you dont fake any euthanasia for the video like a lot other RUclipsrs im seeing, like dam we just talking about plants my dude no need to act like ya won the lottery!
love the vibe!
Ha thank you! I'm guessing you meant enthusiasm not euthanasia 😂 Really appreciate it!
@@JBNat haha yeah didnt noticed the autocorrect on that 🤣
Thank you so much, so informative. I never knew that the plants have to take in the neem oil, instead I thought that you had to apply it to the bugs directly
Really glad you found it useful!
THANK YOU SO MUCH! I have used neem oil as a spray and as you mentioned there are so many reasons why it is not the best solution. I am a container gardener and just struggle so much when I have something that gets infested with aphids or this year it has been cucumber beetles. I will be using this method starting TODAY and I promise to report back in a few weeks. Thank you again!
When I mix in my sprayer, I mix neem and peppermint castile soap together heavily first in a mason jar to emulsify them into a slurry. I then add water to the mason jar and shake it. Then it gets added to my sprayer and topped off with the appropriate amount of water. It has always been well mixed this way.
I will also try the root soak this season to see if it does the trick.
Great tip!
Very helpful, thanks!
I use insecticide soap on leave and neem drench for roots for indoor plants :)
I thought about this too and watered my indoor plants with neem, one weekend later the look healthier. I have ben having pest problems and this seem to work great.
Glad it's working for you!
Thanks for this video bro i needed this.
Glad I could help!
You're brilliant and adorable! Thank you for sharing!
Wow I just purchased neem oil but there was no directions for application. Your channel popped up on my feed and glad to have stumbled on it. Thanks for sharing, new subscriber here. I have never heard this method yet and normally people here in the Philippines use it as spray. More blessings to your channel.
🙏❤️
As one who can attest to the devilish mess it makes of sprayer, this is a godsend. Made the error of not thoroughly cleaning after last season. It became like axel grease. Nearly threw the sprayer out, it took so many hours, but finally got it going. Thank you so much for modeling this method!
Hope you enjoy!! I just made up a fresh mix yesterday for my peppers, it really is so much easier
Absolutely not, unless you directly spray them with it.
Great video! Thank you! Does the neem oil spray/drench help with brown spots on leaves?
I don’t like the idea of spraying Neem but using it as a drench is a game changer! Thanks so much for sharing JB! fingers crossed it will give me the edge on my current leaf miner battle 🙃
Thank you so much! Be interested to hear how you get on with leaf miner. I'm not sure if neem is so good at deterring 'single' attacks. Because it takes quite a few days to impact the pests, it's really good against infestations of smaller things, but one single leaf miner grub can probably do a lot of damage before the neem impacts its hormones/feeding cycle. Potentially? Not sure!
@@JBNat Yeah will do! I’ve had outbreaks of black and white fly which I’ve dealt with but leaf miner is a constant low level thing going on
@Sara H did you try it? What were the results?
Is there some kind of competition on RUclips to see who can make a 2 minute video last the longest,,?
Great instructional video! I found it very easy to follow. You kept it simple, concise, and without unnecessary chitchat! THANK YOU! How often should I use this soil drench to keep aphids, white flies, and fungus gnats at bay on my plants?
Thank you very much! I would use it maybe once every three weeks if you've had historic issues with pests, but they're not on your plants yet. If you have an infestation it's a very slow acting pesticide so you'll probably want to up it to around once a week for 2-3 weeks.
It does seem to be a better way to use it!
Hi JB, thanks so much for the info, I have just started using neem oil - I have spider mites on an indoor fig tree, that was in the house when we bought it ( tree is about 10 feet high, and then the 2 branches turn and are growing ll to ceiling w/2 skylights ). It started dropping yellowed leaves, w/brown spots, and when I researched another site, found out they were spider mites.
The site I was on, was using CJ's dead bug 1st, and said that it might have to be used again, 1 or 2 more times (7 days apart), if it was an infestation. She also said that, CJ's only works for the adult stage, and to use the neem oil spray, because it will "suffocate the eggs". I also would prefer using a soil drench, as long as it is safe, but did you come across any info about the "egg phase" and what works, while you did your research? thanks
"ExPESTo…PatroNEEM!"
(Sorry, JB! Couldn't resist on account of the vocal, facial, beard, and accent resemblance.)
Brilliant video!
almost gave up on my garden this morning, took a breath came in and saw this on my feed. I will try it and thank you. Who knows maybe I can salvage the passion
Hey Sean it really means a lot that you've said that about one of my videos! Can I ask you what you're having trouble growing and what pests you've got?
@@JBNat hey thanks. I've been being overrun by aphids. I feel silly because watching videosmthey seem like a pest everyone deals with but gets through. They are just laying waste to my melons plants...I think the reality is i need to find and solve the ants first?
@@SeanMurphy74 ants is an interesting one, a lot of people say they will protect the aphids from predators, however I've definitely seen ladybirds happily laying waste to the aphids and munching away whilst the ants just watch. If aphids are the main issue I would definitely recommend neem oil - make sure you get 100% cold pressed!
great advice
Really good information;my harder is ALL in pots; and earwigs are my problem! Will neem kill them? And do I only spray leaves; or flowers as well
wow, I been wanting to use neem for years but it always burns the leafs, it stays about 80 degrees all the time. Also I fine that warming the water (not hot) warm, mixes better. The sun does a great job of this.
Thank you for your well-produced, clear and concise video on Neem Oil, JB. It's an education I have been seeking for years - always thought that spraying the stuff could be detrimental to beneficial people like ladybugs, etc. and you just confirmed that.
I'm assuming your translation from metric 5L to 1 gallon is to a UK gallon? I'm guessing that translates to about 4 US gals? It's about time the US adopted the metric system, but that ain't gonna happen anytime soon ;-(
Thank you, and yes I didn't know about the metric/imperial use of gallon when I made this to be honest! A gallon here is 4.5L. So the quantities I use for my ten litre watering can match with 2.6 US gallons.
Thank you for the helpful tip. Your videos are so informative. I have a question. How often do you do these neem oil soil drench?
Thank you! I would suggest a maximum of every two weeks. Two weeks is okay if you have an infestation of something, but hopefully it is more preventative, in which case every 3-4 weeks is better.
Thank you for your two very helpful neem oil videos. My affected brassicas are in the ground rather than pots or raised beds. I’m wondering whether you’ve found the root drench works on plants which are in open ground.
I'll be trying it this year for sure but have found people in the comments saying it works just fine :)
@Naturally JB If the fruit trees are in the ground instead of pots is this method still preferred over spraying the leaves? Or does this predominantly work better for potted and green house only? I've been using Neem oil with bio wash to spray citrus leaves.
Inquiring minds would like to know. Thank you in advance
I’m going to try this on my tomatoes this evening…I hate spraying plants
Nice method of mixing neem oil solution. I will definitely try it.
I'm just wondering if you still have aphid problem now that the temperature in the greenhouse gets pretty high.
Thanks! Because I've been using this root drench since I found the first single aphid, I've not seen any others on my plants! My greenhouse does get hot but with all the vents and door open it's probably cool enough that aphids would still survive in there (maybe?)
I think its so funny how eggplant is aubergine in the U.K. so weird how we have totally different words for some stuff even though it's the same language. Also, your videos are very asmr-ish, your voice is quite relaxing.
Thank you! I try and keep my allotment tours nice and relaxed because they're some of my favourite kind of videos to watch
Thank you so much for sharing this video....Does the soil feel a little different/funky for having been watered with the emulsion? Do you think the soil structure changes somewhat? Clearly it is working for you and that gives me some confidence to try this. Very importantly do you taste the neem in your peppers? These are peppers so you are harvesting intermittently and you can't perfectly time the watering to harvest. I want to try this for my swiss chard which are getting so many leaf miners..
Hello! Certainly never noticed a change in the soil condition, and never noticed any taste changes when using the drench. You can taste it if it's spayed directly onto the leaves though.
Leaf miners might actually not be that affected by neem because its slow acting. They would likely still arrive and damage the plant. Neem would affect their reproduction and digestion, so it will probably mean they do less damage
Thanks for the update. I found using the soil drench kills those pesky Fungus Gnats that live in the soil of my houseplants. How often do you soil drench? Do you water in between drenches. Great video.
I use it around once every 3-4 weeks on my peppers as a preventative. So not too often at all.
Thanks for the video. Will this Neem oil solution have any negative effect if there are fertilizer granules in the soil?
Have you grown sweet red pimientos? They are smaller than red bell peppers. Would like your input on neem oil used in conjunction with Tree paste. Thank you.
Thanks for the video. I have a crepe myrtle tree that is infested with aphids. Would you use the same measurements fir my tree?
We have little hole in our potato leaves. Will using the drench help this and is it ok if some of the drench gets on the leaves?
We are growing them on top of dirt in straw, so it may be a lil messy and wondered about the leaves, I won't drench the leaves, but may get some drench on em. Thank u
Thanks
Thank you for sharing will this help with fungus gnats in the soil do you think? I may have to give it a try 👍🇨🇦🐝 safe
Yes definitely! Neem oil is really effective for fungus gnats!
Thanks for sharing this great tip! Couple questions... I need to treat some large hedges that are 8-10" at the trunk. Any suggestions on how much of the mix to apply and how often? Aphids are my primary insect issue.
To be fair, I would say that for large plants or trees you are better off spraying it onto the leaves. The root drench does work in raised beds and for potted plants, but large established woody plants are likely to have a MUCH deeper root system, the neem would be less likely to make its way into the plant I should think.
Good point. I think I'll still try a good drenching and see what happens. Thanks much! :)
Your other video with Neem oil is my first experience with your channel, then I watched this one. How long have you been doing the root drench method? Seems a lot easier if it is effective. What zone are you in?
I am now a new subscriber and will watch other videos of yours! Greetings from Michigan! 😊
Fantastic Diane! Great to have you subscribed 😁 this year I've only used neem oil on my peppers and as they were all in pots I thought it would be easier to use the drench. Last year when I did the first video I also had issues on lots of other plants which had aphids or whitefly etc. Others in the comments have said they water neem oil into their veg beds and it works really well. So if I get any pests in the beds I'll be using the drench mix straight on the beds :)
In the UK we don't have the same zones as the US, but I'm on the south coast which is one of the mildest places to grow in the UK. Our last frost is usually late March and then our first frost is November/December.
@@JBNat thank you for the quick response. You average frost dates is helpful information, along with the other information you provided. 😊
Brilliant idea how often would you use method on potted plants
It's really as often as you need, I would say once every 2-3 weeks is the norm. I've been doing my peppers about once a month and I've found literally two single aphids all season!
That's an impressive result 👍
Hello, thank you so much. I have really big tamarind trees.. Do I use the entire 1 gallon per tree ? 5 gallon per tree? Less?
Makes sense to drench soil
Hi, can I use this method on my avocado trees? I have borers and don't know what to do.
Great video man. Do you know if root drenching works on corn as well?
It should for sure!
@@JBNat awesome! Thanks man.
I did the dench soil method on a few potted plants yesterday and they are already looking unhappy. Is there a quick fix I should do. Like rinsing out the soil more or something? I was trying to get rid of fungus gnats.
You can use baking soda and warmer water to replace soap
I used neem oil to fight againts Black Spot on Roses , can I used your method ( soil Drench ) to get the same results ?
Thanks for the tips!
I have pretty bad powdery mildew on Butternut, Yellow Zuc, and tomatoes.
I did peroxide a few days in a row.
Milk yesterday.
Today I did Neem oil.
Can I reapply the Neem tomorrow again?
I would definitely wait at least 3-4 days before reapplying. It's hard to make a plant "overdose" on neem, but when you're putting it on the leaves it can alter a lot of things such as; photosynthesis, sun being magnified, transpiration rates etc as it is a thick oil. The emulsifying soap can be harmful as well.
So I'm not 100% but I would take care. People always recommend using great caution when using it on seedlings, so it can definitely take its toll on a plant. But I think it's more the fact that it's a sticky oil and soap, as opposed to anything to do with the active ingredients.
Good luck!
Ear wigs keep eating my brand new leaf growth on my pole beans. They are also in the leaves on my tomato plants, A bit on my pepper plants and a few others. We'll be drenched with neem oil work for the ear wigs?
Wow. You plant in the greenhouse but still got pest? Where did they came from?
wouldnt the soap be bad for the root? ..how often should you be doing this?
Can a neem soil drench be used on container watermelon? Leafminers are terrible!!
For Brassicas I use BT to kill cabbage worms. I'm wanting to use need oil for mu cucurbits and nightshade plants but I'm trying to find an affordable pure need oil.
Hello, Thank you very much for your tips. I want to use the method to my cherry blossom tree. could you tell me how often should I apply neem oil?
Hi! The one thing I really should have mentioned is that this method probably doesn't work that well for trees because of their deep, deep root systems. (Unless the tree is in a pot!) General advice is to apply around once every fortnight.
Jb how often do you use neem drench .
Loved your videos keep posting ..
approx once every 2-3 weeks, important not to overdo it
@@JBNat i hope this helps me to grow peppers .
Ever since i started gardening i haven't been able to grow a single pepper plant .
Because of leaf curl virus . I have a white fly problem in my zone and they carry alot of viruses with them . 🥺🥺🥺
I have an insect issue in my garden bed--could i still use the soil drench method? It is in full sun and so I am worried about burning the leaves if sprayed on, even if sprayed at night.
Hello. Can it kill root knot nematodes too?
Thank you for the information on castile soap. I've found a natural castile soap in a store near me but they use sea salt as a thickener, do you know if sea salt is harmful to plants?
It really depends on the amount and the salinity. In the quantities you use for this mix I'd say it's probably fine though! Most synthetic fertilisers are very high in salt too and plants love it
Hey JB, it is difficult to find Castile soap where I'm from. Are there any alternatives to Castile soap or is it okay to skip the soap altogether? Perhaps I can make the drench in small batches so that the plant in a single pot gets the full concentration of the neem oil and water mix?
Hi, sorry I only just saw this question! I imagine it's a bit late now, but I would say that dish soap can work just fine. I've used dish soap in a pinch for this drench method and the plants were all fine. It's just when you're spraying the leaves that you've gotta beware of.
Hi JB, almost every season I battle with aphids, this season, I spent a lot buying marigolds, petunia, Nasturtiums etc to repel aphids, yet as soon as the heat came in, aphids arrived too. They are all around my pepper plants, egg plants, and some very tiny crawling bug(I don't know the name) that keeps making holes on eggplant and cucumbers leaves.
My question is, do I start the soil drench weekly now without doing foliage spraying? My pepper plant leaves appear disfigured, I don't know if it's the aphids or the extreme heat causing it? Thanks so much for a straight to the point video. ❤❤❤
Hey JB, I have tea tree Castile soap and Peppermint Castile soap.... Can I use either of them? Or I have to get an unscented Castile soap?
Wondering if you can mix a fertilizer like miracle grow in with the neem oil solution to drench and fertilize at same time. I also saw where you can buy a neem organic fertilizer not sure what that is. I’m going to try drench method on my container and raised beds. Your thoughts. Thanks in advance
I don't do them at the same time just in case the salts or chemicals in fertiliser changes the way the neem oil works, but it might be fine! I find in summer I'm watering every two or three days so missing a feed is not likely to cause issues.
Neem fertiliser might refer to neem cake meal. It's a byproduct of the oil extraction process and does contain some of the active ingredient. I use that too from time to time. Applying the oil to a raised bed should work just fine.
Thank you for sharing your recipe. I’ve had some ornamental annuals suddenly wilt and die on me in mixed containers and I’m considering doing a soil drench. I did already sprinkle neem powder around the base of the plant and watered it in.
Have you experimented with neem powder at all? I’m curious if the powder alone will work. Thank you again.
To be honest yes I have tried powder before, but I didn't find it very effective and still had aphid problems!
@@JBNat thank you for responding with that. Helpful to know it didn’t work. I will try the neem oil soil drench soon then. Thank you!
How often do you spray the roots?
so, does it work adding it to the soil- for ex: scale on plants?
Hi JB,
Last year I tried the sprayer method you suggested but found my strawberries really didn't like it it knocked them back quite a lot, have you tried the root drench method on any strawberries
as of yet ?. I have fungus gnats every year and they create havoc with my strawberries which I grow in Pots.
I've never tried it on strawberries but if they're in pots I think it would work very well. I would avoid doing it too close to harvest time but in case it changes the flavour of the strawberries! It shouldn't do, but better safe than sorry
@@JBNat Thanks JB
I plan on using the Neem/Soap on my Pumpkins and Petunias in 2023.
Question:
1. How many times a month would you drench the above Plants?
I would say 2-3 times a month, between once a week to once a fortnight :)
I want to use the drench on a mature purple elder. Not a tree - more of a shrub - but a big one. Do you think 40 litres of drench would do? Or is that too much/little?
Afraid I have no idea regarding trees I'm afraid! Worth a go for you though. 40L doesn't sound excessive.
Whay soap can be used to mix with neem oil? Can medimix hand wash be used?
Have you seen if work with squash bugs?
I read that for spraying you should use it every 2 weeks for treatment and every 3 for prevention, but how often should I use it as a soil drench? I have mostly house plants atm if that helps so all in pots. My outside garden is nonexistent for now. I have root aphids.
I would say the same! Every 2 weeks if it's really bad.