Coffee grounds are a favorite for those who want to kill yard pests without poisoning the ecosystem. This kind of pest killer is easy to find since many households have coffee grounds already.
Coffee grounds are non-toxic and, in very small doses, will not injure pets, small children, or the environment. They are also an inexpensive ingredient for a pest control for anyone who regularly consumes coffee.
Coffee grounds will kill bugs that may be beneficial to your garden. If you're concerned about plants in the area you are treating, never use the coffee grounds "straight" because of their high acid content. Neutralize the acidic content of the coffee grounds by mixing them with four parts shredded leaves to one part coffee grounds, or a mixture of coffee grounds, shredded leaves, wood ash and lime. Sprinkle the grounds lightly on the area where pests reside.
If you don't drink coffee at home, check with local coffee shops about taking some of their used grounds. Starbucks, for instance, introduced a program called Grounds for Your Garden in 1995 that gives customers a free 5-lb. bag of coffee grounds for gardening needs.