Casey Kellar, author of The Good Earth Home & Garden Book, has a not-too-messy alternative for organic gardening enthusiasts who want to give their plants a helping hand. She recommends mixing equal parts of water and tuna “juice”—the liquid you normally drain from canned water-packed tuna (about 1/2 cup each). Then add a drop of unscented mild detergent to the mix, and pour it into a bottle. Shake and use immediately.

It’s a bit stinky, Kellar admits, but she says plants absolutely adore her “fish fertilizer.” You can order her book through Amazon.com.