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Cover Crops for Vegetable Growers

Forage radishForage radish

Forage radish PDF file

Forage radish is a fall-seeded Brassica that is not winter hardy. This crop forms thick, white tap roots that can reach lengths of 8-14 inches, most of which are underground. Radishes are excellent at breaking up shallow layers of compacted soils, earning them the nicknames “biodrills” or “tillage radishes.” A thinner extension of the tap root can penetrate deeper layers of compaction. The roots die over the winter and leave channels so that the soil dries and warms up faster in the spring. Forage radishes also suppress fall weeds.

Land preparation
Smooth seedbed, well-drained but with adequate moisture.

Seeding rate
Drill 10 lb/ac (drilled in good conditions) to 13 lb/ac (broadcast or drilled in challenging conditions). Higher rates give weaker growth.
Drilling gives a much better stand, so broadcasting should be reserved for when the soil is too wet to drill. After seeding, roll the ground to improve seed-to-soil contact but do not break up soil aggregates.
Plant at a depth 1/4-1/2 inches.
Can be planted with 40 lb/ac wheat for spring cover and weed suppression.

Seeding date
4-10 weeks before frost. (Late August is ideal. Early September in warm sites.)

Seed Source
Lancaster Agricultural Supply (Cedar Meadow Forage Radish), Steve Groff Seeds, Bird Hybrids, Agriculver, Preferred Seed (Groundhog).

Little maintenance required.

None; they winter-kill in most New York winters. After mild winters, survivors should be killed with herbicide or mowing before seeds harden.

Forage radishes give less ground cover in the fall than mustard, rape, or turnip, but have comparable biomass.
Do not use in rotations with Brassica vegetable crops.
Radishes are magnets for flea beetles, but less so in the fall.

Download Forage Radish guide from Ray Weil, Univ. of Maryland