The nutrient analysis for organic fertilizers is often lower than those for synthetic ones. That's because labeling laws allow only the immediately available nutrients to be listed, not the total. The nutrients in most organic fertilizers aren't very soluble, so they're released gradually. Over time, however, the total amount of nutrients released from organic fertilizers is higher than the label suggests. An organic fertilizer may contain necessary nutrients besides N, P, and K. Bonemeal, for example, is high in calcium as well as phosphorus.
Liquid seaweed contains many micronutrients.
Read the label carefully for information on other materials the fertilizer contains, what it's made from, and what effect the material has on plants and soil organisms. Solid fertilizers, which you apply dry, may be fine powders, large granules, or something in between. Fertilizers you apply wet may come as powders that you dissolve in water or as concentrates that you dilute with water. Dry fertilizers work more slowly but last longer. You can spread a dry fertilizer evenly over a large area, a method called broadcasting.