The time for late-summer seeding (not fall seeding!) of perennial legumes in the northern quarter of Illinois is here. Let's review management suggestions for seeding.

Since alfalfa needs 6 to 8 weeks of growth, or be six to eight inches tall, prior to a killing frost, August 10-15 are the preferred seeding dates. For the central half of Illinois, the suggested dates are August 30 to September 4, and for the southern quarter September 5 to 10. Cool-season perennial grasses can be seeded one to two weeks later. Warm-season perennial grasses should not be seeded until the spring.

Planning ahead is critical for alfalfa and grass seedings. Be sure there is no residue carryover potential from previously applied herbicides. Have perennial weed problems been controlled? Soil tests should have been taken and any corrective limestone already applied. Fertilizer can be applied during seedbed preparation.

If there is not adequate soil moisture to establish the stand, seed should not be planted. It is very risky planting seeds into dry soil.

A firm seedbed is needed to ensure good seed-to-soil contact. Follow the "footprint guide"- soil should be firm enough for a footprint to sink no deeper than one-half inch. A general rule of thumb is that seeds should not be planted deeper than five times their diameter. For most forage crops, the seeding depth should not exceed one-half inch on medium and heavy textured soils, and one-inch on sandy soils.

Tilling the seedbed may not be necessary, as no-till forage seedings can be successful. For example, seeding into small grain stubble once the straw is removed.

Do not seed alfalfa following an older established stand. Autotoxic compounds are released by the older alfalfa that inhibits the growth, development, and production of new alfalfa seedlings. If the alfalfa is more than one year of age, it is best to rotate to another crop before going back to alfalfa. If less than a year, alfalfa can be replanted.

Be sure to use high quality seed of adapted, tested varieties and use fresh inoculum of the proper Rhizobium bacteria for the legume seed. Seeding rates are the same as spring seeding, but a companion crop is not recommended. Since weeds are slow to germinate in the late-summer, a preplant herbicide is typically not required. A postemergence herbicide can be used if weed problems develop and become competitive.

Finally, late-summer seeded alfalfa and cool-season grass fields should not be harvested in the fall of the establishment year.

Further information is available in the newly revised Illinois Agronomy Handbook, 24^th Edition available at the University of Illinois Publication Plus website, https://pubsplus.uiuc.edu/C1394.html (phone 1-800-345-6087), or contact your University of Illinois Extension office.