How do you get rid of fungus gnats?

I had great success following this tip when I had the fungus gnat nightmare.

Get a bag of sandbox sand from your home improvement center. If you can, cover the top of the soil of each plant pot with at least a 1/2 inch thick layer of sand. If your pot does not allow that minimum depth of a layer, you may have to re-pot and then top with sand.

If you feel that there are "critters" in the bag of sand, use a large disposable aluminum baking pan (you can re-use it for this process) and heat the sand in you oven for about 30 minutes at 350°F. Cool completely.

Place this flexible pan on an old cookie sheet or pizza pan for stability before you put the sand in the pan and then into the oven.

I sure do hope these hints from the folks who responded help you with this frustrating and annoying problem.

Good luck.

They breed in the moist potting soil. One solution is to let your plants really, really dry out. I didn't find that too effective as whenever I watered the plant they started hatching again. The adult gnats can live 7-10 days. Another solution is drenching the soil with Diazinon. I think this has been pulled from the market in the US, but if you are in a different country you may be able to find it. The product I ended up using is called Gnatrol. It is a bacteria that kills the larva of the fungus gnats, but is non toxic to almost everything else. I mixed it up per the package directions and watered the plants with the mixture whenever they needed to be watered. It still takes a week or so for the adult gnats to die, but after that I noticed a great improvement. This is the stuff they use in commercial greenhouses to keep the gnats under control.