I think I have an infestation of fungus gnats (or what looks to be fungus gnats) outside. They're only on the northern side of the house where it gets direct sun only in the middle of the summer. I have plants that like wet, shady conditions there.

The soil may be staying too wet and attracting fungus gnats. What can I do to get rid of them? How can I encourage some natural predators? Will diatomaceous earth work? How close to the plants' roots can I use it?

Thanks!