Bone meal is a popular soil amendment derived from animal bones, primarily used to supply nutrients to plants. This fine powder is inherently a natural product, created from a biological source material. However, whether bone meal is classified as “organic” depends entirely on its processing methods and regulatory certifications. The distinction between a natural product and a certified organic one is a significant point of confusion for many gardeners.
Understanding Bone Meal Composition and Source
Bone meal is a byproduct of the meat and rendering industries, typically sourced from the bones of cattle or fish. The bones are collected and subjected to a manufacturing process to stabilize the material and make its nutrients available for plant uptake. This involves cleaning and then subjecting the bones to high-heat treatment, such as steaming or wet rendering, often ranging from 240 to 290 degrees Fahrenheit.
This process sterilizes the material, removes fat, and makes the bones brittle for grinding. The resulting powder is primarily composed of calcium and phosphorus. Bone meal typically has an NPK (Nitrogen-Phosphorus-Potassium) ratio around 3-15-0, meaning it is a strong source of phosphorus and calcium, with a minor amount of nitrogen and trace elements like magnesium and zinc. The mineral content is mostly in the form of hydroxyapatite, which ensures a slow and sustained release of nutrients into the soil.
The Difference Between Natural and Certified Organic Labeling
The term “natural” simply means the product originates from a plant, animal, or mineral source, which bone meal certainly does. “Certified organic,” however, refers to compliance with strict, government-mandated agricultural standards, such as the USDA National Organic Program (NOP) regulations in the United States.
For bone meal to be used in certified organic production, it must be reviewed by a third-party organization, such as the Organic Materials Review Institute (OMRI). An OMRI Listed product verifies compliance with NOP standards, ensuring that no prohibited synthetic substances were used during processing or handling. This certification provides assurance that the fertilizer aligns with the principles of organic farming.
The term “organic” can also be confusing because it has a chemical definition relating to carbon-containing compounds, which bone meal satisfies as a biological material. For gardeners maintaining an organic garden, the OMRI Listed or USDA Organic seal is the only reliable way to confirm the product is approved for use. Without this specific certification, a bone meal product may not meet the necessary regulatory standards for organic crop production. Therefore, a product is not automatically “certified organic” just because it is a natural derivative; it must pass the regulatory screening process.
Applications and Nutritional Value for Plants
Bone meal is valued primarily as a slow-release source of phosphorus, which is fundamental for plant energy transfer and strong structural development. This nutrient is necessary for robust root systems, making bone meal a frequent addition when planting bulbs, shrubs, and trees. The sustained delivery of phosphorus supports the plant throughout its active growing season.
The high calcium content provides a secondary benefit, as calcium is necessary for cell wall formation and overall plant integrity. Supplying sufficient calcium can help prevent physiological disorders like blossom-end rot in fruiting vegetables such as tomatoes and peppers. Bone meal works most effectively in slightly acidic to neutral soils (pH below 7.0). In highly alkaline environments, phosphorus can bind with other minerals, making it less available for plants to absorb.
Safe Handling and Storage
Since bone meal is a finely ground powder, users should take precautions to avoid inhaling dust particles during application. Wearing a particle mask and gloves minimizes the risk of respiratory irritation and skin contact. Although high-heat processing minimizes pathogens, general hygiene practices, such as washing hands thoroughly after handling, should always be followed.
Proper storage is important, as bone meal can attract domestic pets due to its animal origin. Dogs may attempt to dig up areas where the fertilizer has been applied, so it should be worked fully into the soil immediately after spreading. Store the product in its original, tightly sealed container in a cool, dry area away from children, pets, and foodstuffs.