What To Expect For Late-Planted Wheat

These measures may help compensate for expected yield losses due to late-planted wheat.

Published on: Nov 18, 2011

You likely already know that the optimum period for planting wheat is a two-week window beginning with the Hessian fly-free date, as shown in the accompanying graph. But now, you're more than 30 days past that date.

If you've got your wheat in the ground and emerged, you don't have to read farther. But if you've been kept from drilling by wet soils, consider these tips from John Rowehl, Penn State Extension regional agronomist. They may help later planting compensate for expected yield losses of late planted wheat.

Increase the seeding rate by up to 30% after the optimum seeding date. Planting rate during the optimum period is 1.2 to 1.5 million seeds per acre. Now, 1.6 to 2.0 million seeds is the recommended range. As the days past the optimum date pass, increase toward the higher end of this range. The higher seeding rates compensate for the reduction in tillering.

Figure 1.
Figure 1.

Seeding no-till in corn stalk residue may require an additional 15% increase in seeding rate to compensate under those conditions.

Maintaining proper seeding depth (1 to 1.5 inches) below the surface of the soil, not the residue, is critical to achieving good seed-to-soil contact and proper crown development. Shallow-planted wheat is more prone to winter injury.

Availability of potassium, and especially, phosphorus is very important. Phosphorus-deficient plants don't tiller well and are more susceptible to winter kill. Here's where good soil test records come in handy. If test levels are optimum or less, fertilize with recommended rates.

Normally, 10 to 30 pounds of N per acre is recommended. But for late planted wheat, particularly in fields with little or no manure history, nitrogen rates at the higher end of the range help accelerate growth and stimulate tillering.

How to calibrate seeding rate

Since seed wheat varies in size, calculate the number of pounds per acre by dividing the target population by the number of seeds per pound. You only have to count seeds in the pound once. Then, multiply the seed count by 1.15 to allow for germination and emergence loss.

Or, you can calibrate your target rate by setting your drill to the following number of seeds per foot of row. It's based on 85% emergence:

Wheat Seeds

 7-inch Row

7.5-inch Row

1.2 million

19

20

1.4 million

22

24

1.6 million

25

26

2.0 million

32

34