I once thought along the same lines with the sand treatment, but from what I've heard recently, it's not all that reliable. I don't think it will hurt, and you will end up having light reflect off of it, but you'll eventually end up with a sandy mess for a top dressing.

Maybe think about picking up a few of those non-toxic pest strips, and hang them somewhere above the affected pots. If you can keep them near a light, the adults will gravitate right to them. Just be careful that any fans you may have don't blow them into any foliage, or you'll end up tearing the leaves to get them off. For the larvae, best method to kill them is obviously to be careful about not overwatering. Also, make sure that even after a light watering, there is no standing water in the trays beneath the pots. Take away their moisture, and watch their numbers decline!

Take care. :jointsmile:
Mr. Clandestine Reviewed by Mr. Clandestine on . HELP!!!! GOT GNATS IN MY SOIL WHAT TO DO??? I MUST OF OVER WATERED ANY NATURAL WAYS OR SAFE WAYS TO GET RID OF HELP!!!!! Rating: 5