On a crowded windowsill, fungus gnats can soon spread to every plant
(view from an East Harlem brownstone window)
You go to water your plants and notice little gnats flying about. This can happen from overwatering or introducing an infested plant to the fold.
Isolating the problem plant(s) is the first step. The next important step is to cut back on water. Let the soil get dry in between watering. If it is a plant you love, you will not want to throw it away. The first popular solution is a bug spray, but even a 'botanical insecticide' can be harmful to humans and animals, especially when used indoors, and not easy to dispose of safely.
Molly Hackett of Victor, Montana, sent in a very safe and successful solution which was published in April's Horticulture Magazine: she uses sand.
Covering soil with a half inch of sand stops the gnat larvae from being able to reach the surface. When the existing generation dies, that is the end. It takes a week to see the results, but in the end you have gotten rid of the gnats without using one chemical and without needing to throw away the plant.
Sand can be obtained at the local hardware or pet store.
- Matt at apartmenttherapy dot com