Formula Used
Effective establishment = Germination × Purity × Field emergence × Viability × Establishment × Remaining field factors Required seeds = Target plants ÷ Effective establishment × Reserve multiplier Spacing population = Effective area ÷ (Row spacing × Plant spacing) Seed weight = Required seeds ÷ Seeds per kilogram Seed rate = Seed weight ÷ Effective area Available coverage = Available seed weight ÷ Adjusted seed rate Drill rate = Collected seed weight ÷ Calibrated area
How to Use
Select a calculation mode matching your planting decision. Enter field area, spacing, and crop information. Use local agronomic recommendations whenever available.
Add germination, purity, emergence, and expected loss percentages. Enter seed weight or seeds per package. The calculator adjusts the raw requirement automatically.
Enter inventory, packaging, and price details when needed. Complete drill calibration fields for mechanical planting. Review purchase quantities before ordering seed.
Example Data
| Input | Example value | Purpose |
|---|---|---|
| Area | 1 hectare | Defines the field size. |
| Target population | 250 plants/m² | Sets the desired crop stand. |
| Thousand seed weight | 40 g | Converts seed count into weight. |
| Germination | 90% | Adjusts for laboratory performance. |
| Field emergence | 85% | Accounts for field conditions. |
| Oversowing and waste | 8% combined | Adds a practical reserve. |
Frequently Asked Questions
What is seed rate?
Seed rate is the seed quantity planted per unit area. It may use weight or seed count. Crop needs determine the best basis.
Why does germination affect seed quantity?
Not every seed produces a healthy plant. Lower germination requires additional seed. The calculator corrects the requirement automatically.
What is thousand seed weight?
Thousand seed weight measures one thousand seeds in grams. It converts seed numbers into weight. Seed lots can differ considerably.
Can I calculate seeds from spacing?
Yes, spacing mode uses row and plant distances. It estimates planting stations across the area. Loss factors then adjust seed needs.
How are field losses applied?
Each loss percentage reduces expected surviving plants. Multiple losses are applied successively. This avoids simple percentage overstatement.
Can the calculator handle acres and hectares?
Yes, metric and imperial area units are supported. Rates also convert between common systems. Results show both major rate units.
How does packet mode work?
Packet mode divides required seeds by packet capacity. Packet weight can estimate seed capacity. Purchase quantity always rounds upward.
What does available seed coverage mean?
Coverage estimates the area your inventory can plant. It uses the selected rate or density. Reserve allowances remain included.
How is drill calibration calculated?
The calculator divides collected seed by calibrated area. Wheel revolutions can determine testing distance. It then compares target output.
Are crop presets exact recommendations?
No, presets provide convenient starting values only. Local conditions can change suitable rates. Confirm recommendations with qualified advisers.
Why is purchase weight rounded upward?
Seed often comes in fixed bag sizes. Partial bags may be unavailable. Upward rounding prevents planting shortages.