Plant food from the store isn't cheap, and it often has harsh chemicals. Check out my seven homemade plant food recipes, which are cheap and easy to make, and safe for the environment, pets and people.
Homemade "Miracle Grow": Get a clean glass or plastic jar, put a little water in it. Add egg shells and coffee grounds until it's about 3/4 full. Top it off with water and allow to sit in a cool, dark place for about a week, gently shaking once daily. Strain and use the liquid when ready to feed plants.