Seed Rate Calculator
Use target plants, thousand seed weight, germination and expected field establishment to estimate kg/ha and total seed requirement.
Calculate seed rate from target population
Use target plants, thousand seed weight, germination and expected field establishment to estimate kg/ha and total seed requirement.
How the seed rate calculator works
The target plant population is divided by germination and expected field establishment fractions to estimate seeds that must be sown per square metre. Thousand seed weight converts seed count to mass, and the result is scaled to kilograms per hectare.
When to use this farm calculation
This population-based method is useful when seed lots differ in size or germination. It is more transparent than using a fixed kg/ha rate because it shows how seed quality and establishment assumptions affect the required seed mass.
Inputs, units and assumptions
Field establishment is not the same as laboratory germination. Soil temperature, seedbed quality, sowing depth, pests and weather can reduce emergence. Crop-specific agronomy should determine the target population and realistic establishment percentage.
Practical example
At 250 target plants/m², 40 g thousand seed weight, 95% germination and 85% field establishment, the calculated sowing rate is about 124 kg/ha.
Separate seed count from established plant target
A useful seed rate calculator should not assume that every seed becomes a productive plant. Start with the target established population, then account for germination and expected field establishment before converting seed numbers into weight. Thousand-seed weight or seeds per kilogram can vary by variety, seed lot and grading, so use the value printed on the seed lot certificate when available. This produces a more defensible seeding-rate estimate than relying on a single generic kilograms-per-hectare figure.