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Using neem

Bush Doctor 77

Well-Known Member
I use neem oil mix/Dove soap on a regular maintenance basis up through early bloom, especially outdoors. I know the neem half life in sun, on leaves is about 2 days. I ran some numbers and if you put 1 gram on a plant surface, after 20 days, .00000095 gram will remain, or around a millionth of a gram. Early morning before coffee, but I think my math is right. 25 days is .3 millionths of a gram. In my greenhouse, I spray 30 gms(mls) on 4 plants of a kilo each of final bud, so 4 kilos. Now half a plant is leaf and stem( roughly, so the 4 kilos of bud will have 15 gms total of neem originally or 4 gm/kg roughly. So after 25 days, we have .12 millionths of a gram/kilo.
 
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SmokingWings

Well-Known Member
Interesting way of looking at it. Did you take into consideration the amounts of Neem that break down into other organic compounds as the plant absorbs and metabolizes some of the Neem?

Today is Sunday so I usually spray the plants today or tomorrow.

Dang, now I have to think about this while I mix up my Neem in one bottle and some Nuke Em in the other.

Great day outside. I hope yours looks as nice as ours. No matter what, enjoy the day.
 

Bush Doctor 77

Well-Known Member
Interesting way of looking at it. Did you take into consideration the amounts of Neem that break down into other organic compounds as the plant absorbs and metabolizes some of the Neem?

Today is Sunday so I usually spray the plants today or tomorrow.

Dang, now I have to think about this while I mix up my Neem in one bottle and some Nuke Em in the other.

Great day outside. I hope yours looks as nice as ours. No matter what, enjoy the day.
Mine are doing great. You can check my greenhouse out. The main problem I have is grasshoppers(it's like a plague here this year), and neem doesn't control them.

I did not research the byproducts of break down by the sun. I think the half life is only one day in water/sun.

I used to bathe with neem soap. When my wife was sick, I was so stressed, my immune system became compromised. I developed an allergy to animal mite bites, and I had cats and dogs. Bathing every day with neem soap limited the number of bite sites.

"What happens to neem oil in the environment?

Azadirachtin, a major component of neem oil, is rapidly broken down. Microbes and light break down the pesticide in soil, water and on plants. The half-life of azadirachtin in soil ranges from 3 - 44 days. In water, the half-life ranges from 48 minutes to 4 days. It also rapidly breaks down on plant leaves; the half-life if 1 - 2.5 days. The remaining components of neem oil are broken down by microbes in most soil and water environments." From:

Neem Oil General Fact Sheet
 

myopically

Member
there are great answers here, but why use it as a preventive maintenance? i find that if you use better soils, the pests are not there or you might get a couple fungus flies... then i dust the soil with neam, never getting it on the leaves and even the stalk. i have never needed to use more than two treatments. as far as pests that come from the environment, there are much better organic ways to deal. growweedeasy.com might help, and if not google or duck duck go (recommend), is the great cosmic consciousness.
 

Bush Doctor 77

Well-Known Member
there are great answers here, but why use it as a preventive maintenance? i find that if you use better soils, the pests are not there or you might get a couple fungus flies... then i dust the soil with neam, never getting it on the leaves and even the stalk. i have never needed to use more than two treatments. as far as pests that come from the environment, there are much better organic ways to deal. growweedeasy.com might help, and if not google or duck duck go (recommend), is the great cosmic consciousness.
I have thrips, spider mites and powdery mildew in my greenhouse if I don't use neem. I grow in mother earth, improve it every year, and crop rotate. Neem is organic, but so is cyanide.
 

myopically

Member
that’s serious problems and i’m happy you have it dialed in. i’m relatively new to growing, so when i saw what neam did to leaves, i only used as i described. it’s a pain a lot of times, but maybe a cinnamon spray or something is where i was going.
 

bluter

Well-Known Member
been battling both mites and now fungus gnats with neem. one right after the other. i'm in hempy and fungus gnats generally don't like it, but i converted a gift clone from soil, and pow, pests-a-kim-bo all over the grow.

i iso sprayed a week for the gnats and followed it up with a wk of neem oil mix. pretty much have them finished. i flushed with a heavy 29% h202 and ro mix for gnats. started yesterday and following it up with a daily neem spray to the top of the media. the gift plant was loaded up with them so re-flushed today. everyone is getting h202 with the feeds this week as well.

late summer indoor grows are super vulnerable to pests here
 

Bush Doctor 77

Well-Known Member
been battling both mites and now fungus gnats with neem. one right after the other. i'm in hempy and fungus gnats generally don't like it, but i converted a gift clone from soil, and pow, pests-a-kim-bo all over the grow.

i iso sprayed a week for the gnats and followed it up with a wk of neem oil mix. pretty much have them finished. i flushed with a heavy 29% h202 and ro mix for gnats. started yesterday and following it up with a daily neem spray to the top of the media. the gift plant was loaded up with them so re-flushed today. everyone is getting h202 with the feeds this week as well.

late summer indoor grows are super vulnerable to pests here
For fungus gnats, get some BT and mix it with your water. The cheapest form is mosquito dunks.
 
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