Every year, for various reasons, some wheat is not planted during the optimal range of planting dates. For producers in those situations, there are options, a Kansas State University agronomist said.

Optimal planting dates vary across the state with the earliest range from Sept. 10 to Oct.1 in northwest Kansas, said K-State Research and Extension agronomist Jim Shroyer. In southwest through north central and northeast Kansas, the optimal range is Sept. 15 through Oct. 20. In south central to east central parts of the state, the planting range is Sept. 25 through Oct. 20. In southeast Kansas the optimal range is early October to Oct. 25.

"As the end of the optimal planting range approaches, producers need to consider how rapidly the wheat will germinate and emerge and consider increasing their seeding rate," Shroyer said. "As wheat is planted past the optimal dates, yields can be expected to decrease. In a seven-year study in southwest Kansas, yields from a Nov. 1 planting date were about 23 percent lower than those from the optimal Oct.1 date, and yields from a Dec.1 date were about 40 percent lower than the Oct.1 date's."

Shroyer said that parts of the state have received excellent rains this fall, but soils haven't dried sufficiently to allow planting.

"Some fields that were planted earlier need to be replanted because the rains caused soil crusting, which resulted in poor emergence," he said. "Also, in central and eastern parts of the state, wheat is sometimes planted past the optimal date because it is going in after row crops are harvested."

Generally, when wheat is planted late, there is reduced root and tiller development. This subjects the new wheat to wind damage and increases the possibility of winterkill damage, the agronomist said. So, whenever wheat is planted near the end of or past the optimal planting range, the seeding rate needs to be increased to compensate for the lack of tillering.

"Even with higher seeding rates, grain yields will be lower than if the wheat had been planted at an optimal date and seeding rate, but yields won't be as low as (they would have been) if a lower seeding rate had been used," Shroyer said. "In other words, by increasing the seeding rate for delayed planting dates, the yield decrease is not as severe. When wheat is planted late and it doesn't emerge until after Jan. 1, generally yields will be only 40 to 60 percent of normal."

In western Kansas normal seeding rates are 40 to 60 pounds per acre, but after the optimal planting date has passed, the seeding rate should be increased by about 10 to 15 pounds per acre per week, so that by Nov. 1, the seeding rate should be 100 to 120 pounds per acre, he said. In central Kansas normal seeding rates are 60 to 75 pounds per acre, but after the optimal date has passed, producers should increase seeding rates by 50 percent so that by Nov. 1 the seeding rate should be 120 pounds per acre. In eastern Kansas, where seeding rates are normally 75 to 90 pounds per acre, by Nov.1 through Nov. 10 the rate should be 120 pounds per acre.

"Some producers will plant as high as 150 pounds per acre, but there is no real yield advantage from seeding rates considerably higher than 120 pounds per acre," Shroyer said.

When wheat is no-till planted into row crop stubble, however, seeding rates are typically increased by 50 percent, even when planted during the first half of the optimal range of dates. When the expected planting date is past the halfway mark of the optimal planting range or later, the seeding rate should be 100 to 120 pounds per acre.

"If you have good soil moisture, 1-1/2 inches is a great depth to plant, even if you're planting late," Shroyer said. "I wouldn't go deeper than 1-1/2 inches because the deeper you plant, the cooler that soil is going to be, which will slow early growth. But you don't want to plant so shallow that the crown of the plant is at the surface of the soil."

K-State Research and Extension is a short name for the Kansas State University Agricultural Experiment Station and Cooperative Extension Service, a program designed to generate and distribute useful knowledge for the well-being of Kansans. Supported by county, state, federal and private funds, the program has county Extension offices, experiment fields, area Extension offices and regional research centers statewide. Its headquarters is on the K-State campus in Manhattan.