Late summer seeding time for certain forage crops in the northern-third of Illinois is fast approaching. Let's review some management suggestions for these crops.

Since perennial legumes and cool-season grass seedlings need 6 to 8 weeks of growth or be six to eight inches tall prior to a killing frost, August 15-September 1 are the preferred seeding dates for these crops. 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 problem perennial weeds 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, 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 so a footprint no deeper than one-half inch remains.

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.

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

Do not seed alfalfa following an older established stand. 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 known varieties and use the proper inoculum for legumes. Typically, seeding rates are the same as with spring seeding, but a companion crop should not be included. Late-summer alfalfa, cool-season grass seedings should not be harvested this fall.

Certain annuals may be seeded now to provide forage later this growing season. One option is spring oats seeded into wheat stubble. Based on two years of data from the University of Illinois Agronomy Research Center, Shabbona, four oat varieties seeded at 100 pounds per acre averaged 1.8 tons of dry matter per acre when planted in mid-August and harvested in late October. Crude protein averaged 17.7 percent and relative feed value was 154.

Another option is to seed two bushels of spring oats plus two pounds of turnips per acre in wheat stubble for harvest by grazing or perhaps as silage.

Some graziers have been successful with aerially seeding winter rye, or winter wheat, and/or spring oats into standing corn in late August-early September. Turnips have been included in some of these seedings. The intent would be to graze the small grain forage and corn residue together. This option has some risk as adequate soil moisture must be available for germination and establishment.

Further information is available at University of Illinois Extension offices and in the Illinois Agronomy Handbook, http://iah.aces.uiuc.edu/