Your first instinct may be to toss tea bags and coffee filters after they've fulfilled their duties, but if you rethink that notion, you'll find they can also be used in the garden, in moderate amounts. Add used tea leaves and coffee grounds to the compost pile, and use the compost as mulch; or simply mix them into the ground occasionally, letting the nutrients enrich the soil. (Be sure to remove the tags, strings, and staples from tea bags before using them in the garden.) You'll see a noticeable difference in your acid-loving plants, such as azaleas, rhododendrons, and blueberry shrubs.
Recycling Tea and Coffee
Martha Stewart Living, June 1997