Ann I sprinkle it down in the spring before they come up. It is our rainy season then so the coffee washes into the soil. I had a huge problem and had tried everything. Even the Diatomaceous earth, but the coffee and epsom salt in the Spring seems to be what works best for me. Maybe because I had the good coffee. I was traveling and the company put us in the best hotels. I got some pretty expensive gourmet coffee in the rooms every morning. Everybody in our group that did not drink coffee would give me their coffee so I have enough coffee for the next couple of years.