I also recommend Gnatrol or Knock Out Gnats at the first sign of infestation. But keep in mind that it has a shelf life so just order what you need for this season. You can find it at very low cost at Amazon in the smaller packages. Gnats LOVE laying their eggs in most potting mixes that contain sphagnum peat so avoid buying broken bags!! I made that mistake one year when I bought a bargain bale of Pro-mix that had a hole in it!
