OT: gnats


Esteemed Member
I have a large screened pool deck & would like to place some potted plants inside it. Last year I had a terrible gnat problem once the rainy season kicked in & removed them all. Does anyone know of a tried & true fix for this problem? I'd prefer organic for fear of runoff during deluges. I'm at a loss but miss having select pots of speciman plants inside for ambiance.
I had this problem a few years ago and found this solution to work. Remove the top inch of soil from the pots to remove all gnat eggs and larva. Replace the removed soil with 1" of sand or pea gravel (my chosen method and it looked great) sprinkled with a little ground cinnamon.
Scot's method is excellent. Sharing a similar problem and the way it is solved here. Insect pests swarm high quality mango tree during flowering, infecting a good share of fruits coming. Crushed Tulsi(Ocimum sanctum) leaves with the juice is taken in cocos half shells and it is placed among branches to repel the pests.
I have heard of this remedy, but never tried it personally. However, it has the added benefit of killing mosquito larvae and therefore is readily sold and easy to find. Also available as granules.

Bt israelensis (Bt-i) – Bacillus thuringiensis var israelensis
Bt-i is a highly specific biological pesticide for use against mosquito, black fly and fungus gnat larvae. It may be applied safely to irrigation and roadside ditches, pastures, marshes and ponds, water gardens, flower pots, bird baths, rain gutters…any place there is standing water! Once ingested, Bt-i kills 95-100% of mosquito larvae within 24 hours. Highly effective because it kills these pests before they become biting adults. Will not harm people, pets, wildlife or fish. Mosquito Dunks are a commercial form of Bt-i.