Instead of dumping your coffee grounds in the trash, save them! Spring’s the perfect time to go green. For any acid-loving plants â€” think evergreens, roses and tomatoes â€” coffee grounds spread around the base of the plant will give a nitrogen boost. But take care; as with any fertilizer, coffee grounds are toxic to both dogs and cats, so make sure you’re applying them in a pet-free zone. (Just to be safe, I usually water the grounds in or place mulch over them.) For indoor potted plants like gardenias, skip the messy grounds and simply pour any leftover coffee on the plant. Once every other week or so is plenty. â€” Sarah L.