Like coffee? So does your garden. Save the used grounds from your morning coffee, and use them to fertilize the acid-loving plants in your yard (things like azaleas, hydrangeas and blueberries). Then, after you have that covered, add some to your compost pile. Coffee grounds are a great source of carbon, and will help your compost to cook down faster. Planning a lasagna garden? Use grounds as one of your layers. Trying to keep the neighborhood cats out of your vegetable garden? Yep, they’ll do that too. See? Clearly coffee grounds are too useful to throw away.