The best time to apply grub control is once a year during every July. The product we sell for this is Bonide Annual Grub Control. It MUST BE watered in immediately with 1″ of water (a lot of water). Don’t count on rain or a quick spray from the hose to do the job. Left unwatered, the grub killer breaks down quickly and won’t work. You put the spreader away and get the lawn sprinkler out. Put a small tuna fish or cat food can in the area and, when it is full of water, you have properly watered in the grub killer. If you have a large lawn, do it is sections to insure that the grub control gets watered in quickly after application. Failure to properly water in grub control is the reason many folks don’t get it to work…always read the directions on the product package and, more important, follow them.