Ecology Calculators

Plant spacing calculator

Estimate how many plants you need to fill a garden bed given the area and the recommended spacing.

Plant Spacing Calculator

Table of contents

What is plant spacing?
How to use
Common spacings
Square vs. triangular spacing
FAQ

What is plant spacing?

Plant spacing is the distance between two adjacent plants. It controls how many plants fit in a bed, how much each plant gets in sun, water, and nutrients, and how a mature planting looks. Too tight and plants compete; too loose and you waste space and have bare patches.

For square spacing (the simplest layout), each plant occupies a square patch with side equal to the spacing distance:

plants ≈ area / spacing²

How to use

  1. Bed area — measure your bed in square feet (length × width).
  2. Spacing — the recommended distance between plants in inches. Check the seed packet or plant tag.
  3. Number of plants is calculated instantly.

For a 10 ft × 4 ft bed (40 sq ft) with 12-inch spacing: each plant occupies 1 ft² → about 40 plants.

Common spacings

| Crop | Spacing | |---|---| | Lettuce | 8 in | | Carrots | 3 in | | Tomatoes | 24 in | | Peppers | 18 in | | Onions | 4 in | | Strawberries | 12 in | | Basil | 12 in | | Marigolds | 8 in |

These are starting points — adjust for variety, soil quality, and intensive vs. row planting.

Square vs. triangular spacing

This calculator assumes square spacing (plants on a grid). For triangular spacing (offset rows, used in intensive gardening), you can fit roughly 15% more plants in the same area. Multiply the result by 1.15 for a triangular estimate.

FAQ

What if my bed isn't rectangular?

Compute the area however you want (l × w, or a sum of sub-rectangles, or for circles π × r²) and enter the total in square feet.

Do I count rows or the spacing within rows?

For square planting, spacing is the same in both directions. If you have a different inter-row distance, use the average for a rough estimate.

Should I subtract edges?

In small beds, plants near the edge can lean outward — you may want to use 90% of the area to leave a buffer. For large beds, the edge effect is negligible.