Each cover crop species has unique requirements for best planting dates and seeding rates. They also have specific benefits and drawbacks.
For a summary by species of Minnesota-based research, visit the Minnesota Office for Soil Health.
| Name | Best planting dates | Planting rate |
|---|---|---|
| Millet (foxtail, pearl, etc.) | May 20 to July 25 | 20 to 25 lbs. per acre |
| Sorghum-sudangrass | May 20 to July 25 | 25 to 30 lbs. per acre |
| Sudangrass | May 20 to July 25 | 25 to 30 lbs. per acre (15 to 20 lbs. per acre, acc. Cover Crops Field Guide) |
| Cowpea | May 20 to Aug. 15 | 30 to 90 lbs. per acre |
| Buckwheat | June 10 to Aug. 15 | 45 to 60 lbs. per acre (20 to 35 lbs. per acre, acc. Cover Crops Field Guide) |
| Barley (spring or winter) | July 10 to Aug. 15 | 50 to 75 lbs. per acre |
| Soybeans | July 10 to Aug. 15 | 30 to 40 lbs. per acre |
| Annual ryegrass | July 10 to Sept. 1 | 15 to 20 lbs. per acre |
| Flax | July 10 to Sept. 1 | 30 to 50 lbs. per acre |
| Oats | July 10 to Sept. 1 | 30 to 50 lbs. per acre |
| Triticale | July 10 to Oct. 20 | 50 to 90 lbs. per acre |
| Wheat (spring or winter) | July 10 to Oct. 20 | 50 to 90 lbs. per acre |
| Winter cereal rye | July 10 to Oct. 20 | 55 to 100 lbs. per acre |
| Alfalfa | July 25 to Aug. 15 | 12 to 16 lbs. per acre |
| Red clover | July 25 to Aug. 15 | 8 to 12 lbs. per acre |
| Vetch | July 25 to Aug. 15 | 15 to 25 lbs. per acre |
| White clover | July 25 to Aug. 15 | 5 to 8 lbs. per acre |
| Berseem clover | July 25 to Sept. 1 | 8 to 15 lbs. per acre |
| Crimson clover | July 25 to Sept. 1 | 10 to 15 lbs. per acre |
| Canola | July 25 to Sept. 15 | 2 to 5 lbs. per acre |
| Forage turnip | July 25 to Sept. 15 | 1 to 4 lbs. per acre |
| Mustard | July 25 to Sept. 15 | 4 to 8 lbs. per acre |
| Radish (tillage, daikon, etc.) | July 25 to Sept. 15 | 8 to 15 lbs. per acre (5 to 10 lbs. per acre, acc. Cover Crops Field Guide) |
| Field or winter pea | July 25 to Sept. 20 | 30 to 90 lbs. per acre (50 to 80 lbs. per acre, acc. Cover Crops Field Guide) |
-
Brassicas tend to decompose quickly in the spring. It’s believed that nitrogen becomes available earlier in the growing season due to this fast decomposition.
-
Grasses aren’t considered to be nitrogen sources. However, as the plant material decomposes, nitrogen is released and some will become available for the cash crop.
-
Mixtures of two or more cover crop species will provide more benefits than a single species.
We’ve rated cover crops on how effective they are at providing various benefits, using the following grading system:
Excellent ****
Very Good ***
Good **
Fair *
Brassicas
| Name | Nitrogen source | Nitrogen scavenger | Erosion preventer | Weed fighter | Subsoiler | Forage value |
|---|---|---|---|---|---|---|
| Canola | -- | *** | ** | ** | ** | * |
| Forage turnip | -- | *** | ** | *** | -- | ** |
| Mustard | -- | *** | ** | ** | ** | * |
| Radish (tillage, daikon, etc.) | -- | *** | ** | *** | **** | ** |
Broadleaves
| Name | Nitrogen source | Nitrogen scavenger | Erosion preventer | Weed fighter | Subsoiler | Forage value |
|---|---|---|---|---|---|---|
| Buckwheat | -- | *** | ** | *** | -- | -- |
| Flax | -- | ** | * | -- | ** | -- |
Grasses
| Name | Nitrogen source | Nitrogen scavenger | Erosion preventer | Weed fighter | Subsoiler | Forage value |
|---|---|---|---|---|---|---|
| Annual ryegrass | -- | *** | *** | ** | **** | *** |
| Barley (spring or winter) | -- | *** | *** | *** | ** | ** |
| Millet (foxtail, pearl, etc.) | -- | *** | *** | *** | ** | ** |
| Oats | -- | *** | *** | *** | * | *** |
| Sorghum-sudangrass | -- | **** | *** | **** | ** | **** |
| Sudangrass | -- | **** | *** | **** | * | **** |
| Triticale | -- | **** | **** | *** | ** | *** |
| Wheat (spring or winter) | -- | *** | *** | *** | ** | *** |
| Winter cereal rye | -- | **** | **** | **** | *** | *** |
Legumes
| Name | Nitrogen source | Nitrogen scavenger | Erosion preventer | Weed fighter | Subsoiler | Forage value |
|---|---|---|---|---|---|---|
| Alfalfa | *** | ** | *** | ** | *** | **** |
| Berseem clover | **** | ** | *** | ** | * | *** |
| Cowpea | *** | * | ** | ** | -- | ** |
| Crimson clover | *** | ** | ** | ** | ** | *** |
| Field or winter pea | ** | ** | ** | * | * | *** |
| Red clover | **** | ** | **** | *** | ** | *** |
| Soybeans | ** | ** | * | ** | -- | ** |
| Vetch | **** | ** | ** | ** | ** | * |
| White clover | ** | ** | *** | ** | -- | *** |
Midwest Cover Crop Council’s Minnesota Cover Crop Decision Tool
Midwest Cover Crops Field Guide
USDA-ARS cover crop chart: From the U.S. Department of Agriculture Agricultural Research Service (USDA-ARS) Northern Great Plains Research Laboratory
Cover Crops Learning Center: From North Central Region-Sustainable Agriculture Research & Education (NCR-SARE)
Reviewed in 2020