🌱 Plant Population Calculator — Plants per Square Metre
Calculate plants per square metre from seeding rate, seed weight and germination. Verify your crop establishment and identify issues early.
Quick answer: Wheat target: 180-220 plants/m². Canola: 40-60 plants/m². Below target reduces yield. Above target increases lodging risk.
🌱 Calculate Plant Population
📐 How Plant Population Is Calculated
Seeds per m² = (Seeding rate (kg/ha) × 1000) ÷ (Seed weight (g/1000 seeds) × 10)
Plants per m² = Seeds per m² × (Germination % ÷ 100) × (Establishment % ÷ 100)
- Calculate seeds per m² — from seeding rate and seed weight
- Account for germination — multiply by germination percentage
- Account for establishment — multiply by field emergence rate
- Compare to target — adjust future seeding rates if below target
📊 Worked Example
Wheat seeded at 100 kg/ha, seed weight 45g/1000 seeds, germination 95%, establishment 85%.
Seeds per m² = (100 × 1000) ÷ (45 × 10) = 222 seeds/m²
Plants per m² = 222 × 0.95 × 0.85 = 179 plants/m²
At 179 plants/m², this crop is slightly below the 200 target. Increase seeding rate to 112 kg/ha next season to reach target.
❓ Frequently Asked Questions
Plants per m² = (Seeding rate × Germination % × Establishment %) ÷ (Seed weight × 10). Or count plants in a 1m² quadrat and average over 10 locations.
Target 180-220 plants/m². Below 150 reduces yield. Above 250 increases lodging risk. Dry areas target lower (150-180), high rainfall target higher (200-240).
Use a 1m² quadrat (1m × 1m frame). Count all plants inside. Take 10 random samples across the paddock. Average the counts at 3-5 leaf stage.
Poor germination, deep sowing, soil crusting, insect damage (wireworm, earth mite), disease (damping off), dry conditions after sowing, or incorrect seeding rate.