Castor meal is used as a slow-release organic fertiliser. It supplies mainly nitrogen, with smaller amounts of phosphorus and potassium, and adds organic matter to the soil as it breaks down.
Growers apply it directly, or fertiliser makers blend it into pellets and organic mixes for farms, nurseries, gardens and turf. It cannot be used as animal feed, as covered in why castor meal cannot be fed to animals.
What it supplies
Nutrient content varies with the seed, the process and how much hull is in the meal. Suppliers commonly quote a few percent nitrogen and lower levels of phosphorus and potassium. Treat any figure as an illustration and ask for a test report on the lot you buy.
Because the nitrogen is bound in protein, it is released as soil microbes break the meal down. That gives a slower, steadier release than many mineral fertilisers. Growers also value castor meal for organic matter, and some report it helps deter certain soil pests. Treat any such claim with care, as label claims are regulated in many markets.
How it is used
- Field crops and orchards: spread and worked into the soil before planting or around trees.
- Vegetables and horticulture: used in organic and conventional systems as a base fertiliser.
- Blended products: mixed with other organic materials and pelleted by fertiliser makers.
- Potting and garden mixes: used in some retail products, with care over pet safety.
- Turf and landscaping: used in some organic turf feeds.
Organic farming use
Castor meal is a plant-based input, and many organic growers use it. Whether a specific product is allowed in certified organic farming depends on your market's organic rules and your certification body's list of approved inputs. Ask your certifier before you buy, and ask the supplier whether the meal is solvent extracted, since some organic schemes look at how the input was made.
What to put in the specification
- Nitrogen, phosphorus and potassium, with the test method named.
- Moisture, for storage and to avoid caking.
- Oil content, which shows whether it is expeller cake or DOC.
- Form: powder, granules or pellets, and size range for pellets.
- Sand and foreign matter.
- Packing: bag type and weight, or bulk in containers.
- Any heavy metal or contaminant limits your fertiliser law sets.
Supply and handling
Gujarat is the centre of Indian castor crushing, so castor meal is mostly sourced there. Supply follows crushing, which follows the castor seed crop and oil demand. See what castor meal is and whether it can be used as fertiliser for the basics. The dust is allergenic, so handlers should wear masks, and fertiliser and feed should never share containers or bags.
How we help
We find castor crushers who sell meal for fertiliser, check their storage and packing, and have nutrient content tested at an NABL-accredited lab. We then inspect the goods and supervise loading. Ask for a free sourcing review.