In article <19970728024500.WAA02145 at ladder01.news.aol.com>,
Fikeland <fikeland at aol.com> wrote:
>Don't know if this is the right newsgroup to post this on but it's the
>only one that remotely matches the topic ...
rec.gardens would be better.
>My houseplants are breeding tiny black gnats that are driving me crazy! I
>was concerned it was the soil so I replanted every plant in the most
>expensive and clean potting soil my nursery carries. Yet the gnats came
>back. I would appreciate any suggestions on how to get rid of this
>infestation. (My nursery is stumped.)
They are probably fungus gnats. They live on rotting organic matter in
the soil. The easiest way to control them is to keep the soil surface
dry. One method is to put a cm. or two of sand on top of the soil surface.
A dry surface deters the gnats from laying eggs on the soil.
If you want to actually spend money of the problem, the yellow sticky
traps sold to catch white flies are even more attractive to fungus gnats.
There's also a Bt formulation for them, as well as some chemical pesticides.
I'm amazed your nursery is stumped, since fungus gnats are ubiquitous.