Fertilize Your Organic Garden

Organic fertilizers generally come from plants, animals, or minerals. Soil organisms break down the material into nutrients that plants can use. Some organic fertilizers contain significant amounts of only one of the major nutrients, such as phosphorus in bone meal, but they often have trace amounts of many other beneficial nutrients. In addition, some gardeners add organic material that improves soil structure and supports soil microorganisms, which helps make nutrients available more quickly, especially in warm weather when they are more active. As a general rule, organic fertilizers release about half their nutrients in the first season and continue to feed the soil over subsequent years.

Examples of organic fertilizers:

Plant fertilizer - sea kelp (seaweed), alfalfa meal, corn gluten meal and cottonseed meal. 

Green manure - living cover crop plants turned into the soil.

Natural fertilizer from animals - Whether by land, by air, or by sea, animals, fish, and birds all   provide organic fertilizers that can help plants grow. Most animal-based fertilizers provide lots of nitrogen, which plants need for leafy growth.

Mined natural fertilizer - Rocks decompose slowly into soil, releasing minerals gradually over a period of years. Organic gardeners use many different minerals to increase the fertility of their soils, but it's a long-term proposition. Some take months or years to fully break down into nutrient forms that plants can use, so one application may last a long time. 

How To Get Started - The best way to evaluate your own situation is to start with a  soil test. 

source by: https://www.groworganic.com/fertilizers/organic-fertilizer.html