Gnat Control

Last week I decided to put a few plants outside, then bring back indoors. Sure enough I found a few gnats soon afterwards, so I did some research and came up with a fairly comprehensive article I wanted to share. Such things as potato slices and peroxide are new 2/me.

Hope it helps:

http://www.smallfootprintfamily.com/controlling-fungus-gnats-organically

Potato slices - Controls larvaeSlice raw potatoes into 1-inch by 1-inch by 1/4-inch pieces. Place the slices next to each other on the surface of your potting media to attract fungus gnat larvae. Leave the potato slices in place for at least 4 hours before looking under them. (Be prepared to be grossed out a bit.) Once you have seen just how bad the problem is, replace the potato slices every day or two to catch and dispose of as many larvae as you can, and consider adding additional control measures.

Hydrogen Peroxide – Controls larvae
Mix one part 3% hydrogen peroxide with four parts water. Allow the top layer of your soil to dry, and then water your plants with this solution as you normally would. The soil will fizz for a few minutes after application; this is normal. The fungus gnat larvae will die on contact with the hydrogen peroxide. After a few minutes the fizzing stops and the peroxide breaks down into harmless oxygen and water molecules. Repeat as needed.

Sweet info, ive never had gnats in the past but if i ever do this should defiantly help a lot. I love the method with the H2o2.. never thought that would kill them so easyly.

CaliMackdaddy said:

Sweet info, ive never had gnats in the past but if i ever do this should defiantly help a lot. I love the method with the H2o2.. never thought that would kill them so easyly.

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I'm bound to get them again, it's unavoidable growing indoor/outdoor where I am. I've tried coffee grounds as a top dress w/no success...next time I'll slice some potatoes.

Sunbiz1 said:

I'm bound to get them again, it's unavoidable growing indoor/outdoor where I am. I've tried coffee grounds as a top dress w/no success...next time I'll slice some potatoes.

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I heard tobacco spray works also but it never worked on my blackberry bush that had gnats.

Hit them with bt. I just had the same problem and wiped them out in one day.

I got a free batch of them with the Humboldt mix I tried out. Never using it again. I plan on mixing nematodes into my soil batches from now on so they can go to battle anything in there while my mix cooks. If you use organics, I would recommend not using the hydrogen peroxide as it will also kill out the microbes you work so hard to cultivate. If you do this, I would probably reinnoculate with a tea or something after you water with peroxide. The potatoe slices are interesting. I have never heard of that, but its worth a try. Sometimes simpler is better.

NightbirdX said:

I got a free batch of them with the Humboldt mix I tried out. Never using it again. I plan on mixing nematodes into my soil batches from now on so they can go to battle anything in there while my mix cooks. If you use organics, I would recommend not using the hydrogen peroxide as it will also kill out the microbes you work so hard to cultivate. If you do this, I would probably reinnoculate with a tea or something after you water with peroxide. The potatoe slices are interesting. I have never heard of that, but its worth a try. Sometimes simpler is better.

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Yep, the worst offenders are the bagged products we all purchase...compost in particular. Even when stored indoors, I won't buy a bag of anything if I see so much as a pinhole. They hate me at the local Home Depot b/c I'm always disassembling their pallets.

I'm going to research this peroxide method a bit more today, my only concern is how it would affect beneficial organisms.

Peroxide does not work. It only kills the flyers and all bacteria. Not the larva Fish oil works but eventually the gnats become immune to it like neem oil. Its inhibitor too. The only thing that got rid of them for good is sprinkling diatomaceous earth all over. If any type of bug or larva touches it or eats it. It dehydrates them and punctures them. Ripping the bug apart from the inside out.

Do not use potatoe slices. That attracts more gnats than you already have. Gnats like moisture and organic material.

Predatory nemetodes do work but they are sensitive to temp. If it gets too hot or too cold they die off.

I sprinkle cinnamon on top of my soil. works like a charm and the plants love it!

PixiDustr said:

I sprinkle cinnamon on top of my soil. works like a charm and the plants love it!

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Hmm, according to the article you need Ceylon cinnamon, so you're saying the run of the mill kitchen variety is effective as well?.

Cinnamon - Controls larvae and damping off
Cinnamon powder is a natural fungicide that has been shown to be particularly effective against damping-off. It helps control fungus gnats by destroying the fungus that the larvae feed on. Only true Ceylon cinnamon, or Cinnamomum verum, will work. Simply sprinkle enough cinnamon to form a visible layer across the top of your potting media, and repeat every few weeks, if needed. DO NOT use to control fungus gnats in worm bins as cinnamon will kill your worms. Where to find true cinnamon powder online.

hyroot said:

Peroxide does not work. It only kills the flyers and all bacteria. Not the larva Fish oil works but eventually the gnats become immune to it like neem oil. Its inhibitor too. The only thing that got rid of them for good is sprinkling diatomaceous earth all over. If any type of bug or larva touches it or eats it. It dehydrates them and punctures them. Ripping the bug apart from the inside out.

Do not use potatoe slices. That attracts more gnats than you already have. Gnats like moisture and organic material.

Predatory nemetodes do work but they are sensitive to temp. If it gets too hot or too cold they die off.

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I agree with this post use predatory nematodes. They are a microscopic ring worm that eats the larvae. I have had gnat problems in the past and this is the safest most organic way to get rid of gnats. Gnats are more of a nuisance and they are super annoying but in late flower they will get stuck to your sticky buds. Heres a link for predatory insects.

http://www.naturescontrol.com/

BeaverHuntr said:

I agree with this post use predatory nematodes. They are a microscopic ring worm that eats the larvae. I have had gnat problems in the past and this is the safest most organic way to get rid of gnats. Gnats are more of a nuisance and they are super annoying but in late flower they will get stuck to your sticky buds. Heres a link for predatory insects.

http://www.naturescontrol.com/

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TY for this and to the poster you quoted as well, that clears up a few myths.

Question for you/all.

What is the best top dressing to use for prevention?. Gnats LOVE the worm castings I've been using, I'm tempted to use coffee grounds and simply scrape them off when I bring them back in. Grounds are great 4/blueberries and azaleas, but most cannabis strains don't care for acid.

Sunbiz1 said:

TY for this and to the poster you quoted as well, that clears up a few myths.

Question for you/all.

What is the best top dressing to use for prevention?. Gnats LOVE the worm castings I've been using, I'm tempted to use coffee grounds and simply scrape them off when I bring them back in. Grounds are great 4/blueberries and azaleas, but most cannabis strains don't care for acid.

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A lot of growers I know who dont go the nematode route will mix top dressing with Diamatacious Earth ( DE Earth) its a fine powder that cuts up the bodies of gnats making them not want to drop larvae in the soil or you can just sprinkle a top layer of DE earth on the top soil and that works too, it just becomes pasty like and messy but its a real good way to get rid or control gnats the stuff is safe and people will pat their pets down with DE earth to keep critters of their fur.

BeaverHuntr said:

A lot of growers I know who dont go the nematode route will mix top dressing with Diamatacious Earth ( DE Earth) its a fine powder that cuts up the bodies of gnats making them not want to drop larvae in the soil or you can just sprinkle a top layer of DE earth on the top soil and that works too, it just becomes pasty like and messy but its a real good way to get rid or control gnats the stuff is safe and people will pat their pets down with DE earth to keep critters of their fur.

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I'll pick some up at the garden center, TY.

I've heard that a layer of sand on top of the pot will work.The gnats can't penetrate to lay eggs and what larvae there is can't dig out.I don't know,just something I heard.

GoGnats!!!

I swear by this stuff. Its natural too, not a funky chemical. Its mainly Cedar Oil...smells nice to me like a nice old grandmothers wardrobe.

2 cap fulls in 2 gallons of water and BOOM, dead lil' gnats!! I mix a lil into a spray bottle to and spray the girls and the outside of the pots (i use airpots) too!! Good luck

overgrowem said:

I've heard that a layer of sand on top of the pot will work.The gnats can't penetrate to lay eggs and what larvae there is can't dig out.I don't know,just something I heard.

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Same as the DE Earth layer.

840/2 said:

GoGnats!!!

I swear by this stuff. Its natural too, not a funky chemical. Its mainly Cedar Oil...smells nice to me like a nice old grandmothers wardrobe.

2 cap fulls in 2 gallons of water and BOOM, dead lil' gnats!! I mix a lil into a spray bottle to and spray the girls and the outside of the pots (i use airpots) too!! Good luck

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I never used the stuff but have read some good things and bad things about it..same can be said for Azamax and Gnatrol

+1 on the DE. Works great just kinda sux to reapply when you water. Never personally used GoGnats either, but we did sell a ton of it while I worked the hydro store. Guys really liked it.

I use DE top dressing and azamax. I''m gonna try those mosquito puck things.