The label on the package will tell which nutrients are included as well as the sources of the nutrients. The nutrients are identical whether they come from organic or synthetic sources, but the source will affect how fast the nutrients are available to plants. Ammonia sulfate and water soluble fertilizers release most of their nitrogen in a few days and may burn plants if too much is applied. Blood meal releases its nitrogen over a period of months. Deeper rooting trees and shrubs can be fertilized once a year, but shallow rooted plants, such as grass and flowers, will need regular fertilizing throughout the growing season.
Water can move nitrogen several inches in the soil.
Nitrogen that is applied in the fall may be carried too deep into the soil by winter rains. February or March is the best time to feed trees and shrubs. Phosphorus and potassium hardly move in the soil. The feeder roots are found throughout the area under and around a tree, not just at the drip line.