How plant spacing is calculated
For a square grid layout, the number of plants = floor(length in inches ÷ spacing) × floor(width in inches ÷ spacing). A 10 × 4 ft bed at 12-inch spacing gives 10 × 4 = 40 plants. Convert feet to inches first by multiplying by 12.
Worked examples for the same 10 × 4 ft bed: 6-inch spacing fits 20 × 8 = 160 plants, 12-inch fits 40, 18-inch fits 6 × 2 = 12 and 24-inch fits 5 × 2 = 10. Because each direction is rounded down, leftover inches at the end of a row are simply ignored.
The square feet to acres calculator handles the closely related case.
Grid vs staggered planting
This grid method is simple and easy to lay out. A staggered (triangular) pattern can fit roughly 15% more plants in the same space while keeping spacing equal. Plan the soil to fill the bed with the soil calculator.
Typical spacings to enter: lettuce 8 in, carrots 3 in, bush beans 6 in, peppers 18 in, tomatoes 24 in and courgettes 36 in. Square-foot gardening uses a similar grid but varies the number of plants per square rather than the spacing itself.
How to use this calculator
Enter the bed length and width in feet and the recommended spacing in inches from your seed packet. The result shows total plants and the row × column grid. Adding compost? Try the compost calculator.
Leave a little room at the bed edges for plants that spread sideways, and remember that tall crops on the sunny side will shade whatever sits behind them.
Frequently asked questions
- How many plants fit a 10x4 ft bed at 12 inch spacing?
- 40 plants in a simple 10 × 4 grid.
- Where do I find the right spacing?
- Your seed packet or plant tag lists the recommended spacing in inches between plants.
- Can I fit more with staggered rows?
- Yes. A triangular, offset layout can fit about 15% more plants at the same minimum spacing.
- Does spacing affect yield?
- Yes. Too tight reduces airflow and yield per plant; correct spacing balances total plants with healthy growth.
- What about irregular or curved beds?
- Split the bed into rectangles, run each through the calculator and add the results. Expect the real total to come out slightly lower, since curved edges waste space a square grid cannot use.