Too bad to hear bout the persistent lil pricks . Hydro shop is pushing nilnat or natnil . Comes in a lil bottle and it's diluted. I'm getting some cus I'm getting a fresh issue and want to eradicate the problem. Peace and good vibes .lol @Seamaiden .First, let me state that I have never eradicated fungus gnats. They're BAD where I am and I've even found them down on the back of the property (I live in California's Sierra Nevada mountains), I've never experienced such a persistent little fucking pest.
When I used DE, I did not find relief. When I used crumbled dunks sprinkled on the surface of the soil, I did not find relief. I used the dunks in the water I used for mixing up fertilizers, found no relief. I found some good relief using Capulator's beneficials, but not eradication. I haven't gotten a hold of Gnatrol, but I do have cedar oil and am able to mix up my own 'cides' using essential oils--no relief.
The issue is the gnats getting into the root zone and laying eggs, the larvae are what damage and kill our plants. So the neem may seem like a good idea, until you go too far and smother your plants. I've done it, and ultimately it not only didn't kill the larvae, it did kill a bunch of veggie starts I had going.
I've done so much trying to eradicate them indoors (NO harsh or persistent chemicals though, I'm fairly married to organic methods) that I've lost track of everything I've done. This includes sandwiching the media between layers of perlite when potting, which didn't work.
So asking *me* what works isn't necessarily a good idea, because the only way I've seen that stops them from eating up whatever I'm trying to grow inside is to plant it in pure perlite. Everything I've discussed has worked well for pretty much everyone else I've seen post about the subject, though.
Sorry, but I've gotta be honest.