“While coffee grounds contain a small amount of nitrogen, these kitchen scraps are not actually fertilizers—not yet,” Leslie F. Halleck, M.S., a certified professional horticulturist and author, explains. It turns out that coffee’s nitrogen, an essential nutrient that plants need to grow, is not readily available in the grounds immediately after brewing. In order to provide any real value to plants, these grounds need some time to break down in a compost pile.