Late Summer Forage Seeding for Hay and Pastures

By Leanna Dupppstadt and Justin Brackenrich et.al 

Late summer seeding of forages is generally the most successful in PA and allow for new or renovated stands to be well established by the following spring, boosting early yields. Spring seedings can be successful as well, but wet soil conditions, increased weed competition, and the possibility of summer droughts, can make it more difficult. Another advantage to fall seeding is having well-established stands in the spring which will be more competitive with weeds. Late summer is also the time when producers are less busy as compared to the hustle and bustle of spring.

For optimum forage crop establishment  , forages should be planted at least 6 weeks before the first killing frost. This means that forage producers in Pennsylvania should seed cool-season perennials between mid-August to mid-September, depending on location. During this time, the weather is still warm enough to encourage establishment while beating the potential extreme temperatures that settle into our state by mid-fall. September rains encourage quick establishment and the warm days boost growth.

Typically, the ideal time to seed cool-season perennial forages across PA is:

• August 10 – August 15 for Northern PA
• August 15 – August 20 for Central PA
• August 20 – September 10 for Southern PA

When renovating or establishing pastures or hay fields  , producers need to pay close attention to two things, seeding depth and seed-to-soil contact. More failures in forage establishment occur because of improper seeding depth than any other cause. Forage seeds are very small and thus have a very small supply of stored energy to support the seedling until it emerges and can begin making its own energy. Seeds placed too deep are not likely to emerge.

Seeding Depth

Optimum seeding depth varies with soil type (sandy, clay, or loam), soil moisture, time of seeding and firmness of seedbed but generally is not more than 3/8 inch deep. A rule-of-thumb is that 5-10% of the forage seeds that are planted, should be on the soil surface after seeding. Ensuring that seeds are placed at the proper depth requires a firm seedbed. It is extremely difficult to accurately regulate seeding depth if the soil is soft and fluffy. On a properly firmed soil, an adult’s footprint should not be deeper than ½ inch, that is the rule-of-thumb regarding soil firmness. Forage seeds should be covered with enough soil to provide moist conditions for germination, but not so deep that the shoot cannot reach the surface.

Seed-to-Soil Contact

Proper seed-to-soil contact can be tricky when no-tilling into an established stand in an effort to restore or improve forage stands and special attention should be paid to seeding depth. Forage seeds need to absorb at least their own weight in water before germination begins. Unless the forage seed has been planted in saturated soils, the water generally moves into the seed from surrounding soil. Adequate seed-to-soil contact ensures maximum water movement into the seed in the shortest amount of time. Field situations that do not promote good seed-to-soil contact, such as cloddy or loose soil, generally results in extended germination periods and sporadic emergence. The use of press wheels on a grain drill or cultipacking after seeding can improve seed-to-soil contact.

If soil conditions are droughty and soil moisture is limited, then it would be best to delay planting. No-tilling maintains existing soil moisture whereas working the ground for summer seedings can greatly reduce soil moisture. If tilling, especially in a dry year, then seeding should be done earlier in the summer to conserve moisture.

Fall, or better called late-summer, forage seedings present the producer with the best opportunity for stand success as well as production success in the subsequent year. Typically fall seedlings will produce slightly less than a maintenance field, compared to a spring seeded forage which can produce as little as 30% of a maintenance forage field.  Using this information for seeding dates, and field prep will help to ensure more success.