Blood meal is an organic fertilizer derived from dried, powdered animal blood, serving as a concentrated source of nitrogen for garden plants. Tomatoes benefit from this nutritional boost, especially during initial growth stages. Its effectiveness depends entirely on correct application methods and precise timing. Gardeners must manage this fast-acting fertilizer carefully to ensure it promotes leafy growth without hindering fruit production.
Blood Meal Composition and Tomato Nitrogen Needs
Blood meal offers a high nitrogen content, typically with N-P-K ratios of 12-0-0 or 13-0-0. This concentration makes it a potent organic source. Once applied, soil microbes break down the organic material, releasing nitrogen quickly for plant uptake compared to slower-releasing amendments.
Nitrogen is necessary for producing chlorophyll and amino acids, which are essential for plant proteins. For tomatoes, this nutrient primarily fuels vegetative growth, resulting in strong stems and deep green leaves. Adequate nitrogen during early stages supports a large, healthy canopy required to maximize sunlight absorption.
Tomatoes demand the highest levels of nitrogen from transplanting until they begin to produce flowers. Supplying nitrogen during this phase helps establish a strong structural foundation. This foundation is needed to support the later weight of developing fruit clusters and maximize yield potential.
Optimal Timing and Methods for Application
The most beneficial time to apply blood meal to tomatoes is at the moment of transplanting or shortly thereafter. This timing aligns with the plant’s intense demand for nitrogen to develop its initial stem and leaf structure. Applying the nutrient too early, before the plant is established in the garden, can result in the nitrogen leaching away or becoming unavailable.
Application of this high-nitrogen product must cease once the tomato plant begins to produce its first flowers or sets small fruit. Continuing nitrogen at this reproductive stage encourages the plant to focus energy on generating foliage instead of fruit. This misdirection can lead to an abundance of leaves but low tomato production.
One effective technique involves mixing the powdered meal directly into the soil about one week before planting the seedlings. Incorporate one to two cups of blood meal per ten square feet, ensuring it is evenly distributed throughout the top six inches of soil. This pre-mixing allows nitrogen release to begin before the young roots arrive.
For established plants, blood meal works well as a side-dressing applied around the base once the plant is actively growing. Scatter one to two teaspoons of the meal in a ring placed approximately six inches away from the main stem. This distance prevents direct contact while positioning the nutrient within the active root zone.
After applying the side-dressing, lightly scratch the blood meal into the soil surface. A thorough watering is necessary to help dissolve the nitrogen compounds and carry them down toward the feeder roots. This makes the nitrogen readily accessible for immediate uptake.
Risks of Overuse and Potential Drawbacks
The primary danger of using blood meal is nitrogen burn, a chemical injury resulting from high salt concentration around the roots. Since blood meal is highly concentrated, applying too much or placing it directly next to the stem can draw moisture out of plant cells. Damage symptoms include the browning or yellowing of leaf edges, indicating root or tissue damage.
Because blood meal is an animal product, its scent can attract animals to the garden area. Dogs, raccoons, and other scavengers are drawn to the smell and may dig up the soil. Mixing the meal thoroughly into the soil, rather than leaving it as a top dressing, reduces this attraction and discourages digging.
Blood meal has a slightly acidifying effect on the soil, which suits tomatoes as they prefer a slightly acidic to neutral pH range. However, repeated heavy applications over multiple seasons can lower the soil pH over time. This reduction in pH may eventually cause issues with the availability of other nutrients, making soil pH monitoring advisable.