two words- fuck all that other shit - beneficial nematodes! you can get the ScanMask brand on ebay for like 20 bucks. one small container will make a mixture to cover like 4000 square feet of plants. I put the whole shit in my five pots, and Emeril was like Bam! and in seven days, no more fucking gnats. you can fuck with all the other snake oil shit if you want to find out the hard way.
-TomM