"I don't remember where i read it but some one mentioned Bounce dryer sheets around the base of the plant."

That would be me.

Actually, I'm using Kirkland brand now.
They are just as effective but the scent is less overpowering.
Cheap too!
Just bought 500 sheets for about $8.
Have not seen a single gnat, outside!
Good stuff!

Aloha,
Weeze