Plant Spacing Calculator
Calculate how many plants fit in a garden bed based on bed size and recommended plant spacing.
How to use this tool
- Enter the garden bed length and width in feet.
- Enter the recommended spacing between plants in inches (from the seed packet).
- The calculator shows total bed area and the number of plants that fit.
Find out exactly how many plants to buy before heading to the garden centre.
⚠ This tool provides general estimates for education only and is not financial, tax or legal advice. Figures may not reflect your situation — verify with a qualified professional.
Formula
Bed area (ft²) = bed length (ft) × bed width (ft)
Plant count = floor( bed area ÷ (spacing (in) ÷ 12)2 )
Each plant is assumed to occupy a square cell of side equal to the recommended spacing distance.
How it works
This calculator divides the total bed area by the square footprint of a single plant (spacing × spacing) to estimate how many plants fill the bed in a uniform grid layout. Converting spacing from inches to feet allows consistent units throughout.
The result is floored to a whole number because partial plant positions are not usable. This approach assumes a simple square grid; triangular or offset planting can fit roughly 15% more plants in the same space.
Worked example
- Inputs: 10 ft long × 8 ft wide bed, 12-inch plant spacing.
- Bed area = 10 × 8 = 80 ft².
- Spacing in feet = 12 ÷ 12 = 1.0 ft. Each plant occupies 1.0 × 1.0 = 1.0 ft².
- Plant count = floor(80 ÷ 1.0) = 80 plants.
Bed area = 80 ft²; plants needed = 80.
Common mistakes to avoid
- Entering spacing in feet when the calculator expects inches (or vice versa), which produces a plant count that is off by a factor of 144.
- Using recommended spacing for mature plant size but planting seedlings at that distance — this is actually correct practice, but gardeners sometimes pack seedlings tighter and then are surprised by crowding.
- Assuming the square-grid model applies to triangular or hexagonal planting patterns, which fit approximately 15% more plants per area.
Key terms
- Plant spacing
- The recommended center-to-center distance between individual plants, usually given in inches on seed packets or plant tags.
- Square grid planting
- A layout where plants are placed at equal distances in both row and column directions, each occupying a square cell.
- Bed area
- The total surface area of the planting bed in square feet, calculated as length multiplied by width.
- Triangular (offset) planting
- An alternative layout where alternating rows are staggered, fitting more plants into the same area than a square grid.
Frequently asked questions
- How many plants fit in a garden bed?
- Divide the bed area (ft²) by the spacing area (plant spacing in ft, squared). For 12-inch spacing, each plant occupies 1 sq ft; an 80 sq ft bed holds 80 plants.
- What is the standard plant spacing?
- Spacing depends on the plant type: lettuce 6–8 in, tomatoes 24–36 in, peppers 18 in. Always check the seed packet or plant tag for recommended spacing.