Purple Top Forage Turnips Brassica Seed

What they do

Cover-crop brassicas such as mustard, oilseed radish and forage turnip grow fast in cool weather, make plenty of biomass, hold soil, break up compaction and suppress weeds. They contain compounds that can help suppress some soil diseases and pests, and they scavenge nutrients well, though winter-killed plants may release nitrogen before the next crop can use it; sow them in an overwintering mix to hold it longer. Some types can be grazed.

Rotation

Do not plant them ahead of cabbage-family vegetables, since they share pests and diseases.

Sowing

Sow 1/4–1" deep depending on seed size. Drill, or broadcast and cover lightly. Spring and late-summer sowings do best; radish and turnip are best sown in late summer or fall so they root well instead of bolting.

Seeding rate

Use the high end when broadcasting. Mustard: 1/4 lb. per 1,000 sq. ft. (5–15 lb. per acre). Oilseed radish: 1/2 lb. per 1,000 sq. ft. (10–20 lb. per acre). Turnip: 1/4 lb. per 1,000 sq. ft. (5–8 lb. per acre).

Soil

Most do well at pH 5.5–8.5 in fertile, free-draining soil. Seed germinates in soil from about 45 to 85°F (7–29°C).

Termination

Mow or till at flowering. For the biofumigant effect, mow at bloom and work it in or tarp it right away. They winter-kill reliably in Zone 6 and colder.

Seeds per lb.

About 206,600 on average.