Gnats and super soil

Hello, I have found that gnats seem to like the super soil. I have an indoor grow and my plants seem unaffected. Are there symptoms I should look for, and if they are not hurting anything, should I even bother getting rid of them. If I am not concerned about pollinators, is it okay to use chemicals like Sevin, or Hotshots flying insect killer?

Yellow sticky traps, thick mulch layer, keep soil from being too wet.

Also diatomaceous earth in a very thick layer will eventually kill them also. Look for food grade!

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Traps and keeping soil from always being wet helps a ton. But i hate recommending mulches. They can boink ur ph. Make sure u read the bags (if they got info)

Food grade DE like Vert said is also awesome. Just get your lebron james clap on with the stuff (dont breathe it tho) Gnats do something weird to roots more then the plant material. Wont seem to affect u to start. But they mutliply…


Yeah, cedar mulch is a no no. We use wheat straw.

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Why no Cedar @AAA?

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You can wipe them out with those yellow sticky pads that I keep getting my hands stuck on , after I don’t see them anymore I remove them

I intend to re-use the super soil and add more to it for my next grow. Will DE mix in okay, or should I skim it off before I mix in the new soil? And being there was no answer to Sevin and flying bug killer spray, I will go with, I should not use it.

Messes with PH, there is some oil in cedar that can be toxic.

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Cool did not know that. What about apple mulch?

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@badmaster1 skim it, or mix it in, its up to you. Just adds additional stalk strengthening silica to the soil. Won’t hurt a thing.


Never tried.
I add all my trimmed cannabis leaves and stems.

You can see the gnats flying around @badmaster1 thats where the yellow sticky pads come in, they just help to show you that they are around and helps control them as they stick to the yellow cards.
Dont use H202 to much as it damages root structures and microbes
If you want to get rid of them before they alter your yeild or kill your plant you use Bti Bacillus thuringiensis israelensis, combined with yellow sticky boards. I have used every other method!!! this is the only one that totally gets rid of them and breaks the cycle. And is totally safe.


insect Frass contains the only plant-digestible form of chitin, which causes the plant to create the enzyme chitinase , a biopesticidal enzyme that breaks chitin down into nitrogen and chitosan , a biofungicide that kills powdery and downy mildew, early and late blight, and grey mold. Chitinase kills root-feeding nematodes and all plant-chewing insects. It also kills fungus gnats within 24 hours after a single top-dress application.


Insect frass huh? Where and how much and how much do I use?

Up to you I wouldn’t touch that shit with a ten foot pool. Read the ingredients and if you don’t recognize one google it and you will then know.
Just my thoughts after looking them up I don’t want them anywhere near me or anything around me. Many other safer options for you and plants.
Too much toxic stuff being sold to “help” us while killing us softly

But those things do kill shit

@fano_man look up insects frass there’s a few dealers that sell it, I use black soilder fly frass about 1 teaspoon per plant soil drench a little goes a long way,

I had a bad fungal gnat problem from overwatering at first. I watered once 1-4 h202-water to kill larvae, mixed bti in top layer, covered soil in DE, placed sticky yellows down and started bottom watering (in my drain tray) and they were gone with a quickness.

As @Hungrybud said.
Bti bti bti. It works.

At first you may not notice anything, but when those gnats get a foothold your grow will turn to crap.

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@Drinkslinger it’s especially bad if you don’t take care of them and they get stuck to your buds during flowering.