How to Compare Organic Fertilizer


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

Step 1

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.

Step 2

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.

Step 3

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.

Tips and Warnings

  • Read organic fertilizer labels to identify the source of materials. Some fertilizers use sewage sludge, which is not permitted within the guidelines provided by the USDA National Organic Program. All fertilizer products can burn delicate plant roots if overapplied. Follow label instructions for amount and timing of application.

Things You'll Need

  • Soil testing kit


  • Utah State University: Selecting & Using Organic Fertilizers

Who Can Help

  • Capital District Community Gardens: Fertilize Your Garden
Keywords: compare organic fertilizers, organic plant care, organic fertilizer information

About this Author

Joan Norton, M.A., is a licensed psychotherapist and professional writer in the field of women's spirituality. She blogs and has two published books on the subject of Mary Magdalene; "14 Steps To Awaken The Sacred Feminine:Women in the Circle of Mary Magdalene," and "The Mary Magdalene Within."