I apologize if this subject has come up before--it's been a long time since I checked in here--but I just bought a bag of Grubex to mix into new potting soil. I have long had problems with grubs in my containers and have previously tried the Milky Spore and nematodes to no avail. Last year, I bought some expensive poison and used that. This year, I want to prevent an outbreak in the first place by using the Grubex. This will only be for roses and other perennial ornamentals and not for tomato or other edibles. Anybody have any experience with this stuff?