Get some sticky pads to go on th floor around your plants.It took some of them and cut a slot in them so as to fit around the stem,flipped them upside down,with the sticky part facing the medium.The gnats love the soil and you can control them but not irradicate them.You still need an insecticidle soap,as suggested in post above! The sticky pads will stop them at different stages,too! Just a preventive trick I learned along the way!

Ga Grown!