Fertilizers are either inorganic, made from non-living material, or organic, from material that originally came from a living organism. More and more gardeners are eschewing inorganic fertilizers because of a concern with protecting the planet from harmful chemicals, and the knowledge that feeding the soil is as important as feeding the plants.
Some gardeners also prefer organic fertilizer suitable for a vegetarian or vegan diet. Many plant by-products exist that serve very well as highly nutritional fertilizer and soil amendments, and are quite inexpensive to purchase.
Alfalfa meal is a source for nitrogen, phosphorus and potassium. Well balanced with carbon, it is easily converted by soil microbes into usable food for the plants. Available at animal feed or farm stores, a 50-lb. bag can last a long time.
If soil has adequate amount of phosphorus, then soy meal is an ideal fertilizer. Lacking phosphorus, soy provides a boost for all the other necessary nutrients. This helps prevent phosphorus run-off which proves to be a problem in many areas. Using soy meal also is an excellent way to prevent plant burning.
Another natural fertilizer, cottonseed is rich in nitrogen, phosphorus and potassium. It slowly breaks down in the soil, releasing its nutrients over a period of time. Cottonseed can be used as an organic amendment to the soil, or spread over the top of mulch.
Used Coffee Grounds
Used coffee grounds are high in nitrogen and protein, easily absorbed into the soil and are available free from the kitchen, or at many national coffee shops. They can be used extensively in the spring and fall, and for light feeding in-between.
If you are fortunate to live by the seashore and can gather your own seaweed, it gives the opportunity to provide a superb fertilizer. Rich in potassium and trace elements, seaweed lacks in nitrogen and phosphorus. This makes it easy to use without fear of risking nitrogen burn on the plants.