Late summer can be an excellent time to establish forage crops, provided there is sufficient moisture for germination and good seedling growth, says Stephen K. Barnhart, Iowa State University extension agronomist. “It is also a good time to seed bare or thin spots in spring established forage stands.”
Use the following steps to improve your chances for successful late summer forage stand establishment. For best results, some preparatory steps a few months, or years, ahead of the actual seeing may be necessary:
- Test soils and apply needed, corrective lime and/or fertilizer during previous cropping seasons; corrective fertilizer can be incorporated during forage seedbed preparation.
- Begin to control problem perennial weeds a year or more ahead of seeding.
- Be careful with herbicide selection in crops grown it the field before the forage seeding because some may have residual soil activity and will harm new forage seedings if proper waiting periods are not observed. Read the labels for details.
Remember, this is late-summer seeding, not fall seeding, says Barnhart. Therefore:
- Seed as early as possible. Seedlings require six to eight weeks of growth after emergence to have adequate vigor to survive the winter. In Iowa, that means seed by Aug. 10 in the northern third of the state, by Aug. 20 in central parts of the state and by Sept. 1 in southern Iowa. Check with agronomists in your state for local recommendations.
- Forage legumes such as red clover and alfalfa can be seeded up to the dates listed above if moisture is present. Slow establishing species like birdsfoot trefoil or reed canarygrass should be planted in early August in states like Iowa. Most forage grasses such as Kentucky bluegrass, smooth bromegrass orchardgrass, tall fescue and timothy can actually be seeded 15 days or more later than the dates listed above.
- Don’t plant warm-season prairie grasses as a late-summer seeding.
- Make sure there is sufficient moisture to establish the crop. Planting later than the dates mentioned above is sometimes successful depending on fall and winter weather patterns, but there is increased risk of failure and reduced yield potential for the stand as planting is delayed. Again, check with experts in your state for more detailed advice.
- A good rule of thumb for alfalfa is to have 6- to 8-inches of growth before a killing frost.
Prepare a firm seedbed if using tillage. Loose seedbeds dry out very quickly, warns Barnhart. Deep tillage should be completed several weeks ahead of seeding so rains can settle the soil before final seedbed preparation. A cultipacker or roller is an excellent last-pass tillage tool. The soil should be firm enough for a footprint to sink no deeper than 3/8- to 0.5-inches.