Soybean Plant Population Seed Drop Calculator
Calculate soybean seeding rate in seeds per acre from a target plant population, accounting for germination and expected field emergence.
How This Calculation Works
Seeding rate equals the target plant population divided by the expected emergence fraction, which is the germination percentage adjusted for field conditions. For a 140,000 plant target at 90 percent field emergence, seed 155,000 seeds per acre. Row spacing and seeds per foot help set the planter.
Field Calibration & Rate Reference Chart
| Species | Seeds/lb | Target seeds/ac | Bulk lb/ac |
|---|---|---|---|
| Tall fescue | 227,000 | 3,000,000 | 15 |
| Kentucky bluegrass | 1,100,000 | 1,500,000 | 2 |
| Perennial ryegrass | 227,000 | 4,000,000 | 20 |
| Bermudagrass hulled | 1,900,000 | 2,000,000 | 1 |
| Bermudagrass unhulled | 800,000 | 2,000,000 | 3 |
| Alfalfa | 200,000 | 5,000,000 | 28 |
| Winter wheat | 12,000 | 1,200,000 | 105 |
| Soybean | 2,800 | 160,000 | 63 |
| Corn | 1,400 | 34,000 | 27 |
| Cereal rye | 18,000 | 1,200,000 | 73 |
Common Questions
How many soybean seeds per acre should I plant?
Target 140,000 to 180,000 seeds per acre for most row widths, aiming for a final stand of 120,000 to 160,000 plants. Narrow rows and early planting can use the lower end. Adjust for germination and field conditions.
How do I calculate soybean seeding rate from plant population?
Divide the target plant population by the expected emergence fraction. For 140,000 plants at 90 percent emergence, seed about 155,000 seeds per acre. Germination and field conditions set the emergence fraction.
Do soybeans compensate for low populations?
Yes, soybeans branch and set more pods per plant when stands are thin, so moderate reductions often do not cut yield. Very thin stands still lose yield, especially in narrow rows. Aim for a uniform stand within the recommended range.
How do I check my planter's seed drop?
Run the planter over a measured distance and count seeds in the row, or use a seed-count calculator with the row spacing. Compare the result with the target seeds per foot. Recheck after any meter or seed lot change.