Seeding rate formulas
- Rows or square grid:
plants/acre = 43,560 ÷ (row spacing × in-row spacing, in feet) × plants per hill - Plants per foot of row:
plants/acre = 43,560 ÷ row spacing (ft) × plants per foot - Triangular:
plants/acre = 43,560 ÷ (distance² × 0.866) - Seed:
lb/acre = plants/acre ÷ germination × weight of 1,000 seeds (g) ÷ 453,592
Typical plant populations by crop
| Crop | Typical population |
|---|---|
| Corn | 28,000 to 36,000 plants per acre (dryland: 20,000 to 28,000) |
| Dry beans | 70,000 to 110,000 plants per acre |
| Grain sorghum | 40,000 to 100,000 plants per acre, depending on rainfall |
| Soybeans | 100,000 to 140,000 plants per acre (final stand) |
| Wheat | 1.0 to 1.5 million seeds per acre (about 22 to 35 seeds per square foot) |
| Oats | about 1 to 1.3 million plants per acre (2 to 3 bushels of seed) |
| Alfalfa | 15 to 20 lb of seed per acre; 25 to 40 plants per square foot after establishment |
| Tomatoes | 4,000 to 8,000 plants per acre (open field) |
| Peppers | 10,000 to 20,000 plants per acre |
| Potatoes | 14,000 to 20,000 seed pieces per acre |
| Avocado | 70 to 200 trees per acre |
| Coffee | 1,000 to 3,000 plants per acre |
| Bananas and plantains | 450 to 800 plants per acre |
| Citrus | 80 to 200 trees per acre |
These are reference values: the best population depends on the variety or hybrid, dryland or irrigated conditions, soil fertility and your region. Check the seed company recommendation or your local extension service.
Frequently asked questions
How do I calculate plants per acre?
Divide 43,560 square feet (one acre) by the area each plant occupies: row spacing × in-row spacing, both in feet. For example, 30-inch rows (2.5 ft) with plants every 6.5 inches (0.54 ft): 43,560 ÷ (2.5 × 0.54) ≈ 32,200 plants per acre.
What is triangular (hexagonal) spacing?
Plants are set at the corners of equilateral triangles, offsetting each row from the next. At the same distance between plants, it fits about 15.5 % more plants than square spacing and each plant gets more even access to light and soil.
How do I calculate pounds of seed per acre?
Seeds per acre = target plants ÷ germination. Pounds = seeds × weight of 1,000 seeds (g) ÷ 1,000 ÷ 453.6. The seed weight is on the bag or seed tag, often given as seeds per pound instead.
What is the difference between seeding rate and plant population?
Seeding rate is how many seeds you plant; plant population (or final stand) is how many plants actually establish. The gap between them is germination and field losses.