Bone meal is an organic soil amendment made from steamed and finely ground animal bones, commonly used as a natural, slow-release fertilizer. It is highly valued for its high concentration of two nutrients: phosphorus and calcium. Bone meal is not a quick-fix fertilizer, as it must break down in the soil before its nutrients become available to the plant. Effective use requires understanding its composition, proper application methods, and the risks of over-application, especially for tomato plants.
Essential Nutrients Bone Meal Provides to Tomatoes
The primary benefit of bone meal comes from its rich supply of phosphorus (P) (15% to 27% of its weight) and calcium (Ca) (20% to 30% of its content). Phosphorus is an essential macronutrient that plays a direct role in energy transfer within plant cells. This energy is directed toward developing strong, extensive root systems, which are crucial for the establishment and long-term health of the tomato plant.
Adequate phosphorus supports flowering and fruit setting. The presence of phosphorus promotes the formation of buds and flowers, directly affecting the plant’s capacity for producing fruit. A deficiency can lead to stunted growth and poor flower development, resulting in fewer tomatoes.
The calcium content is important for combating Blossom End Rot (BER), a common physiological disorder in tomatoes. This disorder is caused by a localized calcium deficiency in the developing fruit, not a disease. Calcium is necessary for building strong cell walls and overall plant integrity, helping prevent the characteristic sunken, black spots on the tomato’s bottom.
Practical Guide to Bone Meal Application and Dosage
Determining the correct amount of bone meal depends on the application method, as its nutrients must be mixed directly into the soil to be effective. The most beneficial time to apply bone meal is during the initial transplanting phase. For this, mix one to two tablespoons of bone meal into the bottom of the planting hole before setting the seedling.
Mixing the bone meal into the soil ensures the phosphorus is immediately accessible to the new roots. This initial boost helps the young plant develop a robust root structure, which is a significant factor in overall yield. A single tablespoon is sufficient to provide a long-term, slow-release supply of nutrients for the season.
If a mid-season application is necessary, use side dressing when soil testing indicates low phosphorus or calcium. Sprinkle no more than three teaspoons of bone meal around the base of the established plant. Lightly scratch the fertilizer into the top few inches of soil, avoiding root disturbance and keeping it several inches away from the main stem.
Determining Soil Needs and Avoiding Over-Fertilization
Before applying bone meal, conduct a soil test to ensure the amendment is necessary and effective. Phosphorus does not easily leach out of the soil and can accumulate over time. Applying bone meal to soil that already has high phosphorus can lead to nutrient imbalances and is not beneficial for the plant.
Excessive phosphorus can inhibit the plant’s ability to take up other micronutrients, such as zinc and iron, a phenomenon known as nutrient lockout. This results in leaf discoloration and stunted growth. Over-fertilization can also lead to the buildup of salts in the soil, which can burn the plant’s roots and impair water absorption.
The effectiveness of bone meal is influenced by the soil’s pH level. Bone meal is most effective in slightly acidic to neutral soil, ideally with a pH below 7.0. In highly alkaline soil (pH above 7.0), the phosphorus binds with other minerals, making it less available for the roots to absorb, and a different form of phosphorus may be required.