Numerous sources suggest peat as a prime culprit for providing an ideal environment for fungus gnats. I put a layer of sand on top of the soil, at least half an inch deep and try to avoid peat-based mixes. Does anyone have information about fungus gnats and coir? Does using coir as a peat substitute stop or reduce fungus gnats? Also, a web search on fungus gnats will produce many, many results. Kathy Stokmanis Sierra foothills, altitude about 1500 ft., dry, hot summers, mild wet winters. Many plants still in bloom and temperatures in the high 40s at night. Right now it's 70 F, also T-shirt weather.