Gnat control?

What are some organic ways to control gnats that wont hurt microbes?

I have seen people using a layer of sand (2'' thick'') on top of their soil.

Personally my room is sealed enough to release hundreds of ladybugs every now and then. I love it, the gnats not so much I try to keep a happy balance.

bignam said:

What are some organic ways to control gnats that wont hurt microbes?

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A couple simple options are diatomaceous earth, mosquito dunks, and sticky traps. You can pick up a bag of the DM at pretty much any gardening center for $10-$15 for a good sized bag. Apply a layer of it on top of your soil and it will shred the larvae as they make their way to the surface. The sticky traps will catch the adults that are flying/hopping around on the surface, and the mosquito dunks are actually a beneficial microbe that kill the larvae in the soil. You can pick up the mosquito dunks at any big box home improvement center. They actually sell granules now that you can just shake on to the surface of your soil and water in.

Step 1: apply the granules as a top dress and water in to the soil.

Step 2: apply a 1-2 inch layer of DM.

step 3: place sticky traps on or around the soil surface.

step 4: smoke a joint

GreenSanta said:

I have seen people using a layer of sand (2'' thick'') on top of their soil.

Personally my room is sealed enough to release hundreds of ladybugs every now and then. I love it, the gnats not so much I try to keep a happy balance.

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Sand is not such a great idea w/organic soil grows, cuts off the oxygen supply. Aquarium rock or coarse perlite is a better option.

Peace.

i think i have some of those mosquito dunks in my shed i didnt know it kills gnat larvae. i used it because i had an old boat on the side of my house and had a ton of mosquitos because of the standing water in it but im going to use it with the soil and see if that works thats awsome!

Sunbiz1 said:

Sand is not such a great idea w/organic soil grows, cuts off the oxygen supply. Aquarium rock or coarse perlite is a better option.

Peace.

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smart pots should be ok

Mosquito Dunks\Bits or another Bti product are one of the best options. Bti is Bacillus thuringiensis israeli, which makes a toxin that happens to kill certain insects in their larval stages, such as mosquitoes and fungus gnats. The products usually contain the Bti spores and the toxin. Gnatrol is another brand.

DE needs to be dry in order to work; it isn't great for the soil surface in my experience.

Nullis said:

Mosquito Dunks\Bits or another Bti product are one of the best options. Bti is Bacillus thuringiensis israeli, which makes a toxin that happens to kill certain insects in their larval stages, such as mosquitoes and fungus gnats. The products usually contain the Bti spores and the toxin. Gnatrol is another brand.

DE needs to be dry in order to work; it isn't great for the soil surface in my experience.

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Yep. I only use it in veg in large containers where I don't water for several days to a week. Apply the mosquito dunks, water it in, then a layer of DM (that stays dry on the surface), then sticky traps. Done. This combo has worked for me every time.

Hopefully now that I'm amending my own soil I won't have to worry about them. I swear the bags of Happy Frog I used to buy were loaded with gnats.

ive been using fox farm of and the last few times ive used it ive gotten gnats im trying a different brand and doing a side by side also to see if i tell a difference in growth i used to mix of with perlite but this time im mixing in 1:1 of and light warrior.and if those mosquito dunks work i wont have to worry about that problem anymore...

i picked up one of these and put it near my cab's intake and about 4-5 they were all dead!!

Make sure you don't have any pets roaming around those No-Pest strips. I've looked in to the toxicity of those things, and prolonged exposure can be lethal to pets.

I can't imagine that those are too healthy for humans to be breathing either.

Not trying to be a dick, but this is the organics section and those are the furthest thing from organic, imo.

if you let your soil go through a dry phase it'll help. A common mistake is keeping the soil damp all the time. MJ likes dry soil. Most plants in general like a lil dry phase. Obviously i'm not saying to the point that they droop, but drying the soil out will help keep the fungus gnats' larvae from hatching. Sand or DM does work too, a fan pointed at the soil is a good idea also, keeps the gnats from landing.

greasemonkeymann said:

if you let your soil go through a dry phase it'll help. A common mistake is keeping the soil damp all the time. MJ likes dry soil. Most plants in general like a lil dry phase. Obviously i'm not saying to the point that they droop, but drying the soil out will help keep the fungus gnats' larvae from hatching. Sand or DM does work too, a fan pointed at the soil is a good idea also, keeps the gnats from landing.

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I was under that same impression until recently. People using blu mats tend to disagree. When growing organically you are essentially taking care of the microbes in your soil. Microbes like the soil to stay pretty consistently moist. The wet/dry cycles are more geared towards using synthetic nutes where you have already decimated the beneficial beasties in your soil by dumping chemicals in there.

I see your logic, but my advice applies specifically to organic farming, after probably around 45-60 harvests, I've found with the system I use, which is REALLY simple, I have the best results when letting the soil dry out a lil, the roots breathe better. I really have ONLY the advice that I've tried and proven to use. Very simple and I don't wanna sound arrogant but the clubs don't even compete with the results I have. You may be misunderstanding me also, I don't let it get to the point where the surface soil-tension repels the water, just dry to the second digit on my finger. I still stand by my original comment, I have bad results when the soil stays moist. I'm not saying you aren't correct, only that my 20yrs of growing, I have better results letting them dry a lil. I also water differently than most also, using a huge bucket to soak the entire smartpot.

gnatrol works awesome

Insect frass has really worked for me I don't even have to worry about gnats

spinosad has been working well for me and it's organic. GL

JANDE said:

Insect frass has really worked for me I don't even have to worry about gnats

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that's an interesting idea, can you elaborate? Do you use it as a surface amendment? Kinda like DM? I use insect frass also, but as a soil amendment, not on the surface, it'd blow around too much in my garden. Good idea though.

greasemonkeymann said:

that's an interesting idea, can you elaborate? Do you use it as a surface amendment? Kinda like DM? I use insect frass also, but as a soil amendment, not on the surface, it'd blow around too much in my garden. Good idea though.

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I just add it in my stocking with my Guanos, compost, and other ingredients and brew it in with my tea

DO NOT FUCKIN USE NO PEST STRIPS, EVER.

Active ingredient is Dichlorvos. The fact of the matter is that those things are not supposed to be used where food is prepared of served, or even where people\animals actually reside for more than brief periods of time. It is for use in "non-living" areas. Those things emit toxic vapors... the package explicitly states that "This product contains a chemical known to the state of California to cause cancer" but is actually more likely to contribute to symptoms of ADHD in children.

Dichlorvos is a biologically active compound in humans, an acetylcholinesterase inhibitor and therefore has a tendency to be quite toxic.

Pyrethrins would be preferred big time over that crap. Pyrethrins are botanically derived, not generally toxic to people or pets and they break down into harmless byproducts.
Pyrethrin spray will kill adult fungus gnats.

In soil organics biological controls are best. These include the Bti, beneficial nematodes and predator mites. My soil is crawling with Hypoaspis mites, they eat fungus gnats and various other potential soil-dwelling pests, as well as spring tails.