Fish Bone Meal (phos/calcium/ nitrogen)

Fish Bone Meal (phosphorus, calcium, nitrogen)

Fish Bone Meal is a ground fish bone fertiliser that supplies phosphorus and calcium, with some nitrogen and collagen. It suits soil building, potting mixes and a pre-flower top dress for medical cannabis, vegetables and fruit.

At a glance

• Type: single input amendment (ground fish bone)
• Supplier certificate on file: BioGro licence 5252. See the certificate and its dates.
• Analysis: 4% nitrogen, 29.5% phosphorus as P₂O₅ (12.9% elemental P), 25.1% calcium, 0.45% magnesium (United Fisheries certificate of analysis)
• Use for: phosphorus and calcium in soil mixes and potting media, and as a top dress before flowering
• Rate: 8 kg (8 litres) per cubic metre of media, or 400 g (400 ml) per 50 litres
• Bulk density: 8 litres of fish bone meal weighs about 8 kg

What it is

Fish Bone Meal is made from fish bone, dried and ground. Bone is mostly calcium phosphate, so the meal carries about two parts calcium to one part phosphorus by weight, plus the nitrogen and collagen left in the bone.

The analysis below is the United Fisheries certificate of analysis (ICP-MS) for the Calcium Fish Bone MCHC powder we sell. Nitrogen is worked out from the certificate protein figure (24.75% protein divided by 6.25).

What it does

• Supplies phosphorus for energy transfer, root growth and flowering.
• Supplies calcium for cell walls and root tips.
• Adds a small amount of nitrogen (4%) as the bone protein and collagen break down.
• Releases slowly: the phosphorus in bone is not water soluble and becomes available as soil biology works on it.

Analysis

NPK = 4 - 29.5 - 0 (N, P₂O₅, K₂O); elemental 4 - 12.9 - 0

• Nitrogen (N): 4.0% (from 24.75% protein)
• Phosphorus (P₂O₅): 29.47%
• Phosphorus (P, elemental): 12.86%
• Calcium (Ca): 25.14%
• Magnesium (Mg): 0.45%
• Collagen: 14.27%
• Ash: 68.0%
• Moisture: 1.9%
• Mercury (Hg): 0.07 mg/kg

How to use

• Modified media or potting soil: 8 kg (8 litres) per cubic metre.
• Smaller batches: 400 g (400 ml) per 50 litres of media.
• Soil: a handful per plant at transplant or before budding.
• Phosphate stays close to where it lands, so mix it through the root zone rather than leaving it on the surface.
• High soil phosphorus reduces how much a plant trades with mycorrhizal fungi. Test before adding more to a soil that is already high in Olsen P.

Learn more in fifteen seconds

• Phosphorus: what it does
• Calcium: what it does
• Too much P turns mycorrhizae down

Handling and storage

• Wear a mask to avoid inhaling particles and open in a well ventilated area.
• Wear gloves and eye protection, and wash hands after use.
• Once opened, keep sealed and dry.