In ,
Philippe Gautier typed:
Michael Savage wrote:
Hi all

Didn't turn up anything on Google on this one, except an unanswered
query in a longer post about Banana plants. Wonder if anyone can
shed light on this.

I have had tiny flies (3-4mm, with wings held back along the body)
skittering about on the surface of some of my pots for some time -
especially the wetter ones (I have some carnivorous plants, sundews
and butterworts) and the peat-free compost.

Cannot answer you question but I'd like to know too. Since I repotted
some of my house plants with peat-free compost, my flat is infested!

Philippe

From another source:

Question: I keep getting little flies on the soil of my houseplants, what's
the cause and can I stop it. I use a multipurpose compost to plant them.

Answer: Those little flies are known as fungus gnats. Annoying, aren't they?
Generally, they result from too much water. Consider watering less often,
especially for foliage plants. If you can't water less, as in the case of
plants that must stay moist at all times, get out a fork and aerate the top
of the soil so the top dries out faster.

other sources say let the compost dry out between waterings.

pk