Using too little seed leaves gaps that weeds fill and reduces final yield; using too much wastes money and can cause overcrowding that stunts plants. This calculator adjusts the standard seed rate for your crop based on your actual germination percentage, so the plant stand you get in the field matches what you intended on paper.
Adjusted Seed Rate = Standard Seed Rate ÷ Germination Rate (as a decimal), then multiplied by your field area. A germination rate below 100% means you need proportionally more seed to achieve the same final plant population.
| Crop | Standard Seed Rate |
|---|---|
| Wheat | 45-50 kg/acre |
| Rice (direct seeded) | 8-10 kg/acre |
| Maize | 8-10 kg/acre |
| Cotton | 6-8 kg/acre |
For 10 acres of wheat at a standard rate of 50 kg/acre, but your seed lot tested at 85% germination: Adjusted rate = 50 ÷ 0.85 = ≈58.8 kg/acre. Total seed needed = 58.8 × 10 = ≈588 kg, about 12% more than the standard 500 kg you'd have used without checking germination — a small extra cost that prevents a thin, weed-prone stand.
Standard seed rates assume 90-95% germination. If your seed lot tests lower — common with older or improperly stored seed — using the unadjusted standard rate will leave your field understocked, reducing potential yield before the season even starts.
Count out 100 seeds, place them on damp paper towel or in moist soil, and count how many sprout after the crop's typical germination period (usually 5-10 days). The percentage that sprout is your germination rate to enter into this calculator.
Yes, though separately from germination — many farmers increase seed rate by 10-20% for late-sown wheat or other crops to compensate for reduced tillering time, since later-sown plants have less time to branch out and fill gaps.
Yes — excessive seed rate causes overcrowding, increases competition for light and nutrients, and can raise disease pressure from reduced airflow between plants, sometimes lowering yield even though more seed was used.