Organic fertilizers are sold as single ingredient additives or blends that supply nutrient needs for specific plants and flowers. Ingredients in organic fertilizers come from sustainable sources such as rock powder, seaweed, animal manure, cottonseed meal and blood and bone meal. There are 13 essential nutrients in these ingredients that are necessary for healthy plant growth. Soil varies in organic matter content and essential nutrients and testing may be necessary to determine your soil condition. When you know what the soil needs, you know what to feed it.
Determine Soil Needs and Compare
Test the soil by following instructions on the soil kit label. They are available at garden centers. The results show which nutrients your soil needs.
Choose a single ingredient organic fertilizer high in the nutrient your soil lacks. Nitrogen is the most commonly needed nutrient in soil, according to Utah State University. It supports all phases of plant growth and is an essential macro-nutrient. Typical sources of nitrogen in organic fertilizers include bat guano, blood meal and fish meal. For soil low in phosphorus, choose an organic single-ingredient fertilizer such as bone meal, soft rock phosphate or fish bone meal.
Choose a blended-ingredient organic fertilizer if the soil test did not show a severe nutrient imbalance. Blended fertilizers for vegetable gardens may include feather meal, fish bone meal, seaweed extract and mined potassium for a balanced nutrient supply. Organic fertilizers provide slow-release of nutrients to benefit plants over time.