By Andrew Frankenfield
Be sure to calibrate your grain drill before you seed your small grains this fall.
The early harvest of corn and soybeans should allow for timely seeding of small grains this fall. The desirable plant population for wheat is 1.3 to 1.5 million plants per acre (28-34 plants/sq ft). This requires a seeding rate between 1.5 and 1.7 million seeds per acre or 20-23 seeds per foot in a 7-inch row. Use lower rates in area 3 (Southeastern Pennsylvania) and higher rates in area 1. See figure 1.7-1 for Small grain management areas in Pennsylvania.
The seeding rate should be based on the number of seeds per acre rather than pounds per acre. Refer to Table 1.7-3 in the Penn State Agronomy Guide when estimating the appropriate seeding rate for various drill row spacings.
Table 1.7.3. Small grain seed or plant densities expressed on a basis of square foot, plants per acre, or seeds per foot. (For example, assuming 85 percent emergence, a target population of 1.3 million plants per acre (30 plants per square foot) would require 1.5 million seeds per acre or 20 seeds per foot of 7-inch row.)
Seeds or plants
per sq ft | Seeds or plants
(millions/acre) | Plants or seeds per foot |
|---|
| 6 inches | 7 inches | 7.5 inches | 8 inches | 10 inches |
|---|
| 24 | 1.05 | 12 | 14 | 15 | 16 | 20 |
| 26 | 1.13 | 13 | 15 | 16 | 17 | 22 |
| 28 | 1.22 | 14 | 16 | 18 | 19 | 23 |
| 30 | 1.31 | 15 | 18 | 19 | 20 | 25 |
| 32 | 1.39 | 16 | 19 | 20 | 21 | 27 |
| 34 | 1.48 | 17 | 20 | 21 | 23 | 28 |
| 36 | 1.57 | 18 | 21 | 23 | 24 | 30 |
| 38 | 1.66 | 19 | 22 | 24 | 25 | 32 |
| 40 | 1.74 | 20 | 23 | 25 | 27 | 33
|
Seeding rates shown in Table 1.7-3 are adequate if you are seeding under ideal conditions; increase these rates when seeding under poor conditions such as a cloddy seedbed or delayed planting date. When seeding more than 2 weeks following the fly-free date, increase the seeding rate by 10% for each week delayed past that date. Do not delay seeding winter wheat because of dry soil.