Fungus Gnats

I have fungus knat and I tried dish liquid and water and that didnt help and I. Don't have no other ideas

i cover the top of the soil with play sand at least a inch. it takes a few weeks to kill them off and you have to do everyplant in the room. also clean everything. as often as you can.place a slice of potatoe in the grow room throw it out every 3 days and replace. they knats will dig throw the sand at shallow places. but they wont have any place to lay eggs. theyll find the potatoe and movin for the kill. you should see less in days but it will take awhile to get rid of all of them. also i try not to go in my room. with clothing iv worn outside.

I love soap & water. It only kills on contact though, but it's very safe, and it's always available. However for bigger bugs, like when I had a few beetles in my soil, I won't hesitate to bust out the insecticidal soap. I deal with gnats pretty much the same was as Shizz with a few minor differences.

I hang yellow fly paper near my plants to catch anything that's flying around. Then I'll let the top inch of soil dry out and add a light layer of diatomaceous earth. If it's really bad I'll do a soil drench using neem oil. The most important thing is to not over react. You want to use the least toxic method as possible and work your way up as needed.

Mosquito Dunks , all you need

^ Mosquito Dunks\Bti (a certain kind of bacillus bacterium) is quite effective at controlling fungus gnat populations. Unlike most other suggestions the Bti actually kills the larval stages of the gnat. This is important due to the life cycle of a fungus gnat, which takes roughly a month. If the measures you take are only to kill the adults you're less likely to be successful. The toxins produced by Bti are very selective and wont harm anything else in the soil.

Here's what I would recommend: get the dunks, which are available at every home improvement center. You can break a single dunk in half or in quarters. Wear a dust mask (latex gloves are good, too). Take a good chunk and break it up with your hands, a hammer, or use a coffee grinder (one you don't use to grind coffee with). Soak the broken dunk chunk in a gallon of water, shaking periodically over the course of a day. Use this water to irrigate your plants with.

Have a vacuum standing by while irrigating the plants. Use the vacuum to the take care of the adults that fly away from the soil to avoid being drowned. Yellow traps are a good idea, too, of course. Repeat the vacuuming daily or at least each time you water, and repeat the Bti application every two weeks. This way you're killing adults as well as larvae and it is much more likely to result in the gnats being wiped out.

While waiting for the other treatments to kick in you could go after them with a vacuum cleaner. I found that method particularly satisfying after finding a stack of month old dishes under my son's bed.

use azamax once and be done with gnats

my question is what do fungas gnats do to your crop?

Virtually nothing. The larva eat fungi and decaying organic matter in the medium. The adults fly around your grow room and lay eggs in the soil, which will eventually result in more fungus gnats... and some might get stuck in the trichomes.

the larva will eat at your roots and the plant will yellow premature

All good advice but the best yet came from Vindicated when he said The most important thing is to not over react. Doing a buch of stuff that doesn't work may be worse than doing nothing at all. My suggestion is to try the sand with a little Diatomaceous Earth (DE) but be careful of over watering . That layer can effect air exchange in the soil.It takes three days to break the reproductive cycle , adults may remain for up to two weeks.And check out https://www.rollitup.org/organics/441074-
how-you-applying-diatomaceous-earth.html , the dunks work great as well and they are an organic bacteria so no negative effects on beneficials .....and good luck...J.L..

Sorry, that was https://www.rollitup.org/organics/441074-how-you-applying-diatomaceous-earth.html

get some sand from your local park or school and put about a inch or 2 on top of the soil


i had a bad fungus gnat problem and i searched far and wide for a simple, cheap solution. the cheapest one was sand, and since I didnt want to go buy any i went to the park down the street and got a bucket full.
i let it sit in water over night, strained it to get all the big rocks and whatever out. did that until it was pretty clean.
then i just took a spoon and made a layer on top of my soil, i put up a couple yellow fly traps from the dollar store.

im gnat free now.

Lmao, thats a great idea about having a dang vaccum present, nice...................I did totaly forget about mosquito dunks this summer until i saw your post, man yeh that reay worked great last summer, I just soak 1/2 dunk and soak in 5 gallon bucket all the time, can refill and reuse until dunk is totaly gone to..........

sm90 does the trick

marcu5 said:

sm90 does the trick

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SM-90 is a wetting agent, how does it kill fungus knats ? I use it when feeding and in foliar spray and I've had knats.How do you use it ?

Jack Larson said:

SM-90 is a wetting agent, how does it kill fungus knats ? I use it when feeding and in foliar spray and I've had knats.How do you use it ?

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i spray my base with it and apply it to my res. gnats haven't been a problem since

Do you use the recommended dosage on the bottle for foliar spray? I believe it's 1:5.

I mix 1 tablespoon sm-90, 1 teaspoon neem oil, and 1 teaspoon karanja oil with 1.5 liters of water as a foliar spray for spider mites. I usually see 1 or 2 fungus gnats flying around, but then again I don't treat the soil.

Neem seed meal is an excellent soil amendment. I've used it as a critter deterrent with pretty good success. Also known as neem seed cake, I tried to top dress with it during a particularly bad fungus gnat infestation of my first grow. Bad idea... it got moldy and stunk so bad it made my fish hydrolysate smell like Hai-Karate in comparison. The trick, as with most other soil amendments, is to thoroughly mix in your soil formula and try to give it a few weeks to cook up.

not organic, but IMID will kill them and their friends (root aphids) for good. it is systemic, so i would feed it up 60 days before harvest.

mg75 said:

not organic, but IMID will kill them and their friends (root aphids) for good. it is systemic, so i would feed it up 60 days before harvest.

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but doesn't this kill off the good stuff too? microbes and bacteria?