According to Ohio State University's Agriculture program, the best time to plant grass seed is from August 15 to September 15 as a general rule. However, for central and southern Ohio it is acceptable to plant the seed any time during the month of September.
Planting later in the fall may result in the grass seed failing to grow sufficiently. The winter weather may result in insufficient growth establishment for the grass to survive, suggests Ohio State University Agriculture program.
Gardeners in central and southern Ohio can usually successfully plant grass seed from October 15 to October 30, Ohio State University Agriculture program points out. The program also states that if these deadlines are not possible, postpone planting until spring as planting in March greatly raises growth production.