vermicast

Vermicast, also called worm castings, is the nutrient-rich material excreted by earthworms as they digest organic matter in a vermiculture or vermicomposting system. It is produced when a worm bin or composting setup processes kitchen scraps, manure, and other biodegradable materials, and the resulting castings are separated from undigested residues and worm cocoons.

Composition and properties: Vermicast contains soil-friendly nutrients and a diverse population of beneficial microorganisms. The exact nutrient content depends on the feedstock but generally includes nitrogen, phosphorus, and potassium in readily available forms, along with trace elements. It also contributes to soil structure by increasing aggregation, improving porosity and water-holding capacity, and supporting microbial activity in the rhizosphere. Many growers report a mild, neutral to slightly acidic pH and low risk of weed seeds compared with raw compost.

Applications: Vermicast is used as a soil amendment in home gardens, landscapes, nurseries, and greenhouses. It can be incorporated into potting mixes, used as a top dressing, or applied as a mulch. It is valued for promoting seed germination and root development and for enhancing plant vigor when used in combination with other soil management practices. It is generally considered safe for organic production when produced from approved inputs.

Production and handling: The quality of vermicast depends on feedstock quality and vermiculture management. Harvesting typically involves settling and sieving to separate castings from residual material. Avoid inputs with high salinity or contaminants, as these can harm worms or affect plant performance.

See also: vermicomposting, compost, soil amendment.