Whether establishing new stands or seeding bare or thin spots in fields seeded earlier this year, this is the prime time frame for late-summer seeding of forage crops, says Mark Sulc, Ohio State University Extension forage specialist.
He lists the following key management steps for successful summertime forage establishment:
1. Apply lime and fertilizer according to a soil test. Since the stand will be used for several years, ideally the soil test should have been taken within the past year.
2. Control problem perennial weeds ahead of seeding. Be careful with herbicide selection because some have residual soil activity and will harm new forage seedings if proper waiting periods are not observed. Be sure to read the labels of any herbicides being considered.
3. Plant new perennial forage stands as soon as possible in August. Seedlings require at least six to eight weeks of growth after emergence to have adequate vigor for winter survival. In northern Ohio, plant during the first two weeks of August. In southern Ohio, plant by Aug. 30. Later planting may work, but there is greater risk for failure and the stand may have lower yield potential next year. The new stand should have 6-8” of growth before a killing frost. Slow-establishing species should be planted as early as possible. Fast-establishing species like red clover, alfalfa and orchardgrass can be seeded up to the dates listed above if moisture is present. Kentucky bluegrass and timothy can actually be seeded 15 days later than the dates listed above.
4. It’s risky to place seeds into dry soil – there may be just enough moisture to germinate the seed but not enough to get the seeding established. Either plant soon after a rain when soil moisture is adequate, or when a good rain system is in the forecast.
5. No-till seedings conserve moisture and can be very successful provided weeds are controlled prior to seeding. Remove all straw from fields previously planted to small grains. Any remaining stubble should either be left standing, or clipped and removed. Do not leave clipped stubble in fields because it will form a dense mat that prevents good emergence.
6. If you’re going to use tillage, don’t over-till and be sure to prepare a firm seedbed. Loose seedbeds dry out very quickly. Deep tillage is not ideal for late summer seedings. A cultipacker or cultimulcher is an excellent last-pass tillage tool. The soil should be firm enough that your boot leaves a print no deeper than 3/8” (you can bounce a basketball on it).
7. Plant the seed shallow (1/4-1/2” deep) and in firm contact with the soil. Carefully check seeding depth, especially when using a no-till drill. A drill with press wheels provides the greatest success with summer seeding. Broadcasting seed on the surface without good soil coverage and without firm packing is usually a recipe for failure in the summer.
8. Use high-quality seed of known forage-type varieties from reputable dealers. Cheap seed often results in lower yield and shorter stand life. Check out variety performance trials from your own and neighboring states.
9. Make sure legume seed has fresh inoculum of the proper rhizobium to ensure nitrogen fixation. If the seed is pre-inoculated, check with the seed supplier to ensure the seed was stored under conditions that guarantees viable inoculant.
10. Don’t plant new alfalfa immediately after an older established alfalfa stand. Autotoxic compounds are released by old alfalfa plants, which inhibit growth and productivity of new alfalfa seedlings. You can seed in alfalfa in late summer to thicken up a new alfalfa seeding that was made this spring because the autotoxic compounds aren’t present in young alfalfa plants.
11. As the stand develops this fall, don’t be tempted to harvest it. No matter how much growth accumulates, it’s usually best to let the cover protect the new crowns during the winter. The only exception to the no-fall-harvest rule for late-summer seedings is perennial ryegrass. If perennial ryegrass has tillered and has more than 6” of growth in late fall, clip it back to 3-4” in November or early December. Finally, scout new seedings for winter annual weeds in October, and apply herbicides as needed. Winter annual weeds are much easier to control in late fall than they will be next spring.“By following these guidelines, and with a little cooperation from the weather, I trust you will have a vigorous and productive new forage stand next year that should yield the same as if it had been planted this past spring,” says Sulc.