Blood meal is an organic byproduct created from the dried, powdered blood of animals, typically sourced from the meat processing industry. This material is transformed into a highly effective garden supplement. Blood meal is one of the most concentrated natural sources of nitrogen available to gardeners. Utilizing this organic fertilizer provides a powerful boost for plants requiring substantial nutrients for robust growth.
Blood Meal’s High Nitrogen Profile
Blood meal is primarily a single-nutrient fertilizer. Its NPK ratio is typically 12-0-0 or 13-0-0, indicating 12% to 13% nitrogen by weight. This high concentration makes it one of the richest non-synthetic nitrogen supplements. Nitrogen is a fundamental building block for amino acids and proteins, directly involved in forming new plant tissue.
The main purpose of applying blood meal is to promote vigorous vegetative growth, focusing on lush, green foliage and strong stems. Plants with a high demand for nitrogen, such as leafy greens, corn, and brassicas, benefit significantly. It is often used to quickly correct a nitrogen deficiency, commonly visible as chlorosis (yellowing of the lower leaves).
The Mechanism of Nitrogen Release
The nitrogen contained within blood meal is not immediately available to plants because it is locked within complex organic compounds, primarily proteins. As an organic fertilizer, it relies on mineralization to release its nutrients. This process begins when soil microbes consume the organic blood meal material.
These microbes break down the proteins, converting the nitrogen first into ammonium and then into nitrate. The rate of this conversion depends on soil conditions. Warm, moist soil with a healthy microbial population mineralizes the blood meal faster, providing a steady supply of nitrogen over several weeks or months. This slow, steady release contrasts sharply with synthetic fertilizers, which deliver nutrients in a rapid, concentrated dose.
Safe and Effective Application Methods
Due to its potent nitrogen concentration, blood meal must be applied sparingly to prevent damaging plants. Over-application can lead to “fertilizer burn,” resulting from excess salts drawing moisture out of the plant tissues. The typical recommended rate is 1 to 2 pounds per 100 square feet of garden area. For individual plants, approximately one teaspoon worked into the soil around the base is often sufficient.
The most effective method is to till the powder into the top few inches of soil before planting. For existing plants, it can be applied as a side dressing worked gently into the soil surface around the base. Following application, it is important to water the area thoroughly. This helps dissolve the nutrients and begins the mineralization process. Blood meal is best used early in the growing season to encourage structural growth and should be avoided near the flowering and fruiting stages, which can be hindered by excessive nitrogen.