Gnatrol works and so do nematodes, use them both. The rest of the solutions are not solutions, your the only ones going down if your using chemicals. Can you afford the treatments. They are expensive and don't work. So spend the money on nematodes. Don't use the hole pack. Save it in the vegetable crisper. You have about a year and a half to use it. They are in a clay carrier and the package breaths. Use a close pin to keep them closed. Keep them in the original card board box and drop them in a 1 gallon zip lock. Through them in with your lettuce and carrots and celery etc. They will keep.
Heres the problem with fungus knats. They are in your drains. Treat those with the nematodes, they won't mind. They like to eat.
Also the peat media is harvested to often. Lots of sedges in it and this is food for fungus gnats. Inoculate your media before potting seedlings in them. The nematodes will find the offenders in the media.
They are intelligent. Like you. You don't have to drench anything. You know who drenches? People who write about growing plants but don't grow them. An eye dropper of nematodes in solution is enough per pot. Keep shaking the bottle to keep them from settling. Use it all. Use a bottle and eye dropper combo, from the pharmacy. The combo is all you need. Keep it clean, rinse and put it down a drain. Any stragglers will just go to lunch.
