how do i get rid of gnats in my house plants?

Answer 1

set out a dish of water with some honey, or vinegar in it, they will be attracted to it, and drown in the water.

Answer 2

Ngats live in potted plants and on aging fruit. Move the plants outside in the shade and don't water for a week. Most plants will tolerate a dry spell. Older plants should be repotted with new soil. The gnats are attracted to pots with rotting roots. When you repot cut the old roots out.
Let green fruit on the table but move mature fruit into the refrigerator, esp bananas.
Put screens on the windows.

Answer 3

Usually a mist of soapsuds does it, but make sure your plant varieties can handle that.