Plant population — the number of plants per unit area — directly drives yield potential for most row crops, and it's determined entirely by your row and in-row plant spacing. This calculator converts your spacing decisions into an expected plants-per-acre figure, so you can check it against the recommended density for your crop before sowing.
Plant Population per Acre = 43,560 sq ft ÷ (Row Spacing × Plant Spacing, both in feet). Entering spacing in centimeters is automatically converted, and the result scales directly with your total field area.
| Crop | Recommended Population/Acre |
|---|---|
| Maize (grain) | 28,000-32,000 plants |
| Cotton | 40,000-55,000 plants |
| Sunflower | 18,000-22,000 plants |
| Vegetables (tomato) | 6,000-10,000 plants |
For maize planted at 75 cm row spacing (≈2.46 ft) and 20 cm plant spacing (≈0.66 ft): Population/acre = 43,560 ÷ (2.46 × 0.66) ≈ 26,800 plants/acre — slightly below the 28,000-32,000 target range. Tightening plant spacing to about 18 cm would bring the population up to roughly 29,700 plants/acre, within the recommended range for maximizing grain yield potential.
Crops like maize and cotton have a fairly narrow optimal population window because individual plants compete strongly for light and nutrients — too few plants wastes yield potential, too many causes barren stalks or reduced boll set. Crops like vegetables tolerate a wider spacing range without as sharp a yield penalty.
Population is inversely related to row spacing — narrower rows fit more rows per acre, increasing population at the same in-row spacing. This is why many modern maize and cotton varieties are bred to tolerate narrower rows for higher populations.
No — beyond a crop's optimal density, added plants compete for the same light and water, reducing per-plant yield enough to offset or even reverse the gain from more plants. Every crop and variety has a specific optimal range rather than a simple 'more is always better' rule.
This calculator assumes uniform row and plant spacing in a single-crop stand. For intercropping or irregular spacing patterns, you'll need to calculate population separately for each crop's actual planted area within the field.