Plant Spacing Calculator

How the Plant Spacing Calculator Works

This calculator tells you how many plants fit in a rectangular garden bed using a simple grid layout. You enter the bed’s length and width in feet, plus the recommended spacing between plants in inches. The tool then returns the total number of plants along with the number of rows (down the length) and columns (across the width).

It works for vegetable beds, flower borders, ground cover, hedging and any planting where you want even, evenly spaced rows.

The Formula

Plants are laid out on a square grid. First the spacing is converted to feet so every measurement uses the same unit:

Spacing (ft) = spacing (in) ÷ 12 Rows = floor(bed length ÷ spacing) Columns = floor(bed width ÷ spacing) Total plants = Rows × Columns

The floor (round-down) step is important: you can only plant a whole row or column that physically fits inside the bed, so any leftover strip is ignored.

Worked Example

Suppose you have a raised bed that is 20 ft long and 4 ft wide, and your plant tag recommends 12 in (1 ft) spacing:

• Spacing = 12 ÷ 12 = 1 ft
• Rows = floor(20 ÷ 1) = 20
• Columns = floor(4 ÷ 1) = 4
• Total plants = 20 × 4 = 80 plants

If you increase spacing to 18 in (1.5 ft) in the same bed:

• Rows = floor(20 ÷ 1.5) = floor(13.33) = 13
• Columns = floor(4 ÷ 1.5) = floor(2.67) = 2
• Total plants = 13 × 2 = 26 plants

Wider spacing dramatically lowers the count because both dimensions are divided by the larger number.

Common Plant Spacing Guide

Use the spacing on the seed packet or plant tag when you have it. These are typical starting points:

Plant	Recommended spacing
Lettuce, radish	6 in
Peppers, bush beans	12 in
Tomatoes, broccoli	18 in
Squash, zucchini	24 in
Shrubs / hedging	24–36 in

Tips for Accurate Spacing

• Measure the bed, not the frame. Use the inside planting dimensions, since the wood edges take up space.
• Round spacing up, not down. When a tag gives a range like 12–18 in, use the larger number for healthier, less crowded plants.
• Consider square-foot gardening. For intensive beds, divide the area into 1 ft squares and place 1, 4, 9 or 16 plants per square depending on the crop.
• Account for paths. If you walk through the bed, subtract path width from the planting area before calculating.

A correct plant count means you buy the right number of seedlings or seeds the first time, avoid overcrowding, and give each plant room to reach its mature size.