Optimal Seeding Rates for Small Grains
Optimum population is a function of the production of environment, the yield goal, and the planting date. A higher seeding rate is required by low tillering varieties.
| Crop | Plant per acre (x 1 million) | Plants per Sq. Ft. |
|---|---|---|
| Winter Wheat | 0.90 - 1.00 | 21 - 23 |
| Spring Wheat | 1.30 - 1.40 | 30 - 32 |
| Durum | 1.30 - 1.40 | 30 - 32 |
| Barley | 1.25 - 1.30 | 28 - 30 |
| Oat | 1.25 - 1.30 | 28 - 30 |
Seeding rates should be increased by 1% for each day planting is delayed up to a maximum rate of 1.6 million seeds per acre. Delay in planting reduces yield potential and tiller development. For winter wheat, seeding rates should be increased if planting is delayed to compensate for increased winterkill potential.
The general formula for calculating a seeding rate is below. Expected stand loss is 10 to 20% under good seedbed conditions. Stand loss will increase with poor seedbed or improper seed placement.
Seeding Rate (lbs. per acre) = ((Desired Stand in Plants per acre) / (1 - Expected Stand Loss)) / ((Seeds per lb.) x (% Germination))
Example of the the equation:
110 lbs per acre = ((1.1 million seeds per acre)/(1-0.15)) / ((12,500 seeds per lb)x(0.95))
| seeds/lb. | 800k | 900k | 1M | 1.1M | 1.2M | 1.3M | 1.4M | 1.5M |
|---|---|---|---|---|---|---|---|---|
| 10,000 | 99.1 lbs/a | 115.5 lbs/a | 123.8 lbs/a | 136.2 lbs/a | 148.6 lbs/a | 161.0 lbs/a | 173.4 lbs/a | 185.8 lbs/a |
| 10,500 | 94.4 lbs/a | 106.1 lbs/a | 117.9 lbs/a | 129.7 lbs/a | 141.5 lbs/a | 153.3 lbs/a | 165.1 lbs/a | 176.9 lbs/a |
| 11,000 | 90.1 lbs/a | 101.3 lbs/a | 112.6 lbs/a | 123.8 lbs/a | 135.1 lbs/a | 146.4 lbs/a | 157.6 lbs/a | 168.9 lbs/a |
| 11,500 | 86.1 lbs/a | 96.9 lbs/a | 107.7 lbs/a | 118.5 lbs/a | 129.2 lbs/a | 140.0 lbs/a | 150.8 lbs/a | 161.5 lbs/a |
| 12,000 | 82.6 lbs/a | 92.9 lbs/a | 103.2 lbs/a | 113.5 lbs/a | 123.8 lbs/a | 134.2 lbs/a | 144.5 lbs/a | 154.8 lbs/a |
| 12,500 | 79.3 lbs/a | 89.2 lbs/a | 99.1 lbs/a | 109.0 lbs/a | 118.9 lbs/a | 128.8 lbs/a | 138.7 lbs/a | 148.6 lbs/a |
| 13,000 | 76.2 lbs/a | 85.7 lbs/a | 95.3 lbs/a | 104.8 lbs/a | 114.3 lbs/a | 123.8 lbs/a | 133.4 lbs/a | 142.9 lbs/a |
| 13,500 | 73.4 lbs/a | 82.6 lbs/a | 91.7 lbs/a | 100.9 lbs/a | 110.1 lbs/a | 119.3 lbs/a | 128.4 lbs/a | 137.6 lbs/a |
| 14,000 | 70.8 lbs/a | 79.6 lbs/a | 88.5 lbs/a | 97.3 lbs/a | 106.1 lbs/a | 115.0 lbs/a | 123.8 lbs/a | 132.7 lbs/a |
| 14,500 | 68.3 lbs/a | 76.9 lbs/a | 85.4 lbs/a | 93.9 lbs/a | 102.5 lbs/a | 111.0 lbs/a | 119.6 lbs/a | 128.1 lbs/a |
| 15,000 | 66.0 lbs/a | 74.3 lbs/a | 82.6 lbs/a | 90.8 lbs/a | 99.1 lbs/a | 107.3 lbs/a | 115.6 lbs/a | 123.8 lbs/a |
| 15,500 | 63.9 lbs/a | 71.9 lbs/a | 79.9 lbs/a | 87.9 lbs/a | 95.9 lbs/a | 103.9 lbs/a | 111.9 lbs/a | 119.8 |
| 16,000 | 61.9 lbs/a | 69.7 lbs/a | 77.4 lbs/a | 85.1 lbs/a | 92.9 lbs/a | 100.6 lbs/a | 108.4 lbs/a | 116.1 lbs/a |
| 16,500 | 60.0 lbs/a | 67.5 lbs/a | 75.1 lbs/a | 82.6 lbs/a | 90.1 lbs/a | 97.6 lbs/a | 105.1 lbs/a | 112.6 lbs/a |
The seeds per pound differ between varieties and even seed lots. If seeds per pound are unknown, count out 100 seed samples several times. Take an average weight per 100 kernels. Use this number to calculate seeds per one pound.
Source: The Small Grains Field Guide A-290 J.J. Wiersma and J.K. Ransom, 2005. Reviewed May 2017.
