Brassica junceaorSinapis albaAnnual broadleaf. Up to 5'. Moderately frost resistant. Produces large amounts of biomass containing high levels of glucosinates that break down into compounds toxic to nematodes and soil-borne disease-causing organisms.
Does not tolerate drought. Allow the plants to grow fairly large to maximize the glucosinate concentration, and then chop fine and incorporate into the soil. Allow 2 weeks for the plant to break down before planting a new crop. Plant 1½" deep in a firm moist seed bed at 15–25#/acre, 1–2#/1000 sq ft.
As cover crop:Best as a fall-planted cover crop to retain nutrients, suppress weeds and improve water penetration. Plant in the spring as a green manure and to suppress nematodes and diseases. (One recent lot came in bags featuring a cartoon knight dubbed “The Nematode Slayer!”)