Seeding Rate Calculator
Calculate exact seed weight requirements for agricultural crops. Adjusts for germination rates, thousand grain weight (TGW), and field hectares.
About
Farmers and agronomists use this tool to calculate the precise weight of seed required to plant a field based on a target plant population. Getting this figure right is critical for yield optimization. A seeding rate that is too low wastes land potential and encourages weeds. A rate that is too high increases seed costs and leads to resource competition among plants. This calculator adjusts for real-world variables like the germination percentage of a specific seed batch and the Thousand Grain Weight (TGW) which varies by crop variety.
Seed batches differ significantly in quality and size. Two bags of wheat might have the same weight but vastly different seed counts depending on the kernel size. By inputting the specific TGW and expected field losses (germination and emergence), this tool provides a highly accurate mass-flow requirement for the drill or planter. This prevents the common issue of running out of seed halfway through a field or ending up with expensive surplus.
Formulas
The Seeding Rate S in kg/ha is calculated using the Target Plant Population D (plants/m2), the Thousand Grain Weight TGW (grams), and the Germination Percentage G.
Note: The factor 100 in the denominator converts the percentage, and the calculation scales to kilograms per hectare automatically. If calculating total seeds needed Ttotal:
Reference Data
| Crop | Avg TGW (g) | Target Density (plants/m2) | Seeding Depth (cm) |
|---|---|---|---|
| Wheat (Winter) | 45 - 55 | 250 - 400 | 3 - 4 |
| Barley (Spring) | 40 - 50 | 300 - 375 | 3 - 4 |
| Corn (Maize) | 250 - 350 | 7 - 9 | 4 - 6 |
| Soybean | 150 - 200 | 40 - 60 | 3 - 5 |
| Canola (Rape) | 4 - 6 | 50 - 80 | 1.5 - 2.5 |
| Oats | 35 - 45 | 250 - 350 | 3 - 4 |
| Peas | 200 - 300 | 70 - 90 | 4 - 6 |
| Rye | 30 - 35 | 250 - 350 | 2 - 3 |