James: I keep a 30 gal plastic trash can as a water supply in my greenhouse and refill it when necessary. I put a 'Mosquito Dunk' or donut in it to control mosquitoes in it, but I use this water to water my plants. May I also have been controlling the gnats in my potting soil this way? I found I could us dollar store knee-high stockings as cheap net bags to put the donut in and tie it off, so when it comes apart, as it will, it is contained in the stocking bag and easily removed. The packet says it is effective for 30 days, which I did not know until I read all these blogs and comments and then went to read my product packet. You can purchase these donuts at Walmart's, Lowe's, Home Depot etc, in their pond supply or garden chemicals sections. Don Kuonen _______________________________________________ pbs mailing list pbs@lists.pacificbulbsociety.net http://lists.pacificbulbsociety.net/cgi-bin/…