Fertilizer · Fertilizer
Bone meal
Also known as: Steamed bone meal
Bone meal is an organic fertilizer made from ground animal bone that supplies slow-release phosphorus and calcium, along with a modest amount of nitrogen, commonly used in organic production and for perennial or bulb crops with sustained phosphorus needs.
Bone meal is produced by grinding steamed or otherwise processed animal bones into a fine powder or granule. It typically analyses around 3% nitrogen and 15% phosphorus (as P₂O₅), together with a substantial calcium content from the bone mineral matrix.
Because its phosphorus is bound in a mineral (calcium phosphate) form that must weather or be mineralised before becoming plant-available, bone meal releases nutrients more gradually than soluble mineral phosphorus fertilizers, making it suited to situations where a sustained, slow-release phosphorus supply is wanted.
Composition and analysis
Bone meal is made by grinding processed animal bone, which is largely composed of calcium phosphate (hydroxyapatite) along with some residual protein-derived nitrogen. Steaming during processing removes fat and reduces pathogen risk while concentrating the mineral fraction.
- Phosphorus content
- About 15% P₂O₅, bound as calcium phosphate
- Nitrogen content
- About 3% total nitrogen, from residual organic material
- Calcium content
- Substantial, as part of the bone mineral matrix
- Release pattern
- Slow, dependent on soil microbial and chemical weathering of the mineral matrix
Nutrients supplied
Bone meal supplies phosphorus and calcium as its primary nutrients, with a smaller nitrogen contribution from residual organic matter. Phosphorus release depends on gradual dissolution of the calcium phosphate mineral, a process influenced by soil pH and microbial activity.
- Phosphorus release is gradual rather than immediate
- Calcium is supplied alongside phosphorus as part of the bone mineral
- Nitrogen contribution is modest and slowly mineralised
Use and benefits
Bone meal is commonly used in organic production systems and for establishing perennial crops, bulbs, and transplants such as garlic and onion, where a sustained phosphorus supply through root establishment is valued over the rapid release of soluble mineral phosphate fertilizers.
- Accepted as an input in many organic farming standards
- Suited to establishment of perennial crops and bulb crops needing sustained phosphorus
- Provides a slow-release alternative to soluble mineral phosphate fertilizers
Application principles
Because phosphorus release is slow, bone meal is generally applied and incorporated well ahead of, or at, planting rather than as an in-season top-dress, and rates are typically guided by soil phosphorus test results rather than a single universal figure.
Environmental considerations
Because bone meal releases phosphorus gradually, the risk of rapid runoff loss immediately after application is generally lower than for highly soluble phosphate fertilizers, though repeated heavy use can still contribute to long-term soil phosphorus accumulation.
Relationships
Evidence-backed connections in the knowledge graph.
Supplies nutrients
Scope & limitations
Geographic scope: Global overview of bone meal as an organic phosphorus fertilizer, commonly used in organic and horticultural production. Sourcing and biosecurity rules vary by country.
Climate context: Warmer, more biologically active soils generally speed mineralisation of bone meal’s organic and mineral phosphorus fractions.
- This entry describes composition and general behaviour; it is not an application rate recommendation for any crop or region.
- Phosphorus release rate depends on soil pH and microbial activity and is not quantified here.
- Sourcing regulations for animal-derived bone meal vary by country and are not detailed here.
Sources
This article draws on the following authoritative sources. See our sources & methodology for how they are selected.
- [1]FAO — Food and Agriculture Organization (opens in a new tab)Authoritative
Food and Agriculture Organization of the United Nations (FAO)
Cited for: Organic phosphorus fertilizer sources
- Type:
- Intergovernmental organization
- Jurisdiction:
- Global
- Accessed:
- 2026-07-12
- [2]USDA NRCS — Natural Resources Conservation Service (opens in a new tab)Authoritative
USDA Natural Resources Conservation Service (NRCS)
Cited for: Slow-release phosphorus behaviour in soil
- Type:
- Government agency
- Jurisdiction:
- United States
- Accessed:
- 2026-07-12
- [3]Cornell CALS — Plant pathology and crop resources (opens in a new tab)High
Cornell University College of Agriculture and Life Sciences
Cited for: Organic fertilizer phosphorus management
- Type:
- University extension service
- Jurisdiction:
- United States (New York)
- Accessed:
- 2026-07-12
- [4]AHDB — Agriculture and Horticulture Development Board (opens in a new tab)High
Agriculture and Horticulture Development Board (AHDB)
Cited for: Organic nutrient management context
- Type:
- Government agency
- Jurisdiction:
- United Kingdom
- Accessed:
- 2026-07-12