Forage Radish
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 7 lb/ac (drilled in good conditions) to 10 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 broadcasting, 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 winter grain if spring cover and weed suppression are desired.
Seed Cost
2024 price: $1.50 - $2.00/lb
Seeding Dates
4-10 weeks before frost. August 1- 20 is ideal in WNY. As late as early September in warmer sites (6b-7a). See online tool to see date for your specific location (Chose “Mustard”).
Time Until Control
None, this cover crop winter kills.
Seed Suppliers
Most seed houses carry cover-crop radishes. Offerings have proliferated greatly, often with provocative variety names. All behave similarly.
Management Tricks
Roll the ground after seeding to ensure good seed to soil contact but not to break up aggregates.
Unavoidable Problems
Less ground cover than mustard, rape or turnip.
Avoidable Problems
Avoid rotations with brassica vegetable crops.
Classic Uses
Remediate deeper compacted soils.
Maintenance
Little maintenance required.
Control
None; they winter-kill in most New York winters. After mild winters, survivors should be killed with herbicide or mowing before seeds harden.
Tips
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
| Management Goal | Planting Time |
|---|---|
| Break Up Deep Compaction | Late Summer |
| Reduce Weeds | Late Summer |
| Reduce Weeds | Summer |