Understanding Plant Population
Plant population is the number of individual plants growing in a given area. It is determined by row spacing and the distance between plants within each row. Optimal plant population varies by crop and is one of the most important factors affecting yield.
Too few plants waste field space and sunlight. Too many plants cause competition for water, nutrients, and light, leading to smaller individual plants, lodging, and disease. Finding the right population maximizes total yield per acre.
Population Formula
Common Crop Populations
| Crop | Row Spacing (in) | Plant Spacing (in) | Plants/Acre |
|---|---|---|---|
| Corn | 30 | 7-8 | 28,000 - 36,000 |
| Soybeans | 30 | 2-3 | 100,000 - 140,000 |
| Cotton | 36-40 | 3-4 | 30,000 - 45,000 |
| Wheat | 7 | 1 | 900,000 - 1,200,000 |
| Sunflower | 30 | 8-10 | 20,000 - 25,000 |
Frequently Asked Questions
What is the optimal plant population for corn?
Modern corn hybrids perform best at 32,000-36,000 plants per acre under irrigated or high-rainfall conditions. Dryland corn in drier areas should target 24,000-28,000 plants per acre to reduce moisture stress.
How does row spacing affect yield?
Narrower row spacing allows plants to capture more sunlight earlier in the season, improving yield potential. Many farmers have moved from 36-inch to 30-inch or even 20-inch rows for corn and soybeans, with yield increases of 2-5%.
Why is germination rate important?
Germination rate determines how many seeds you need to plant to achieve your target population. If germination is 90%, plant 10% more seeds than your target. Seed companies report germination rate on the seed tag.