Plant Spacing Calculator: How Many Plants Fit in a Bed
Enter the bed length and width and the spacing between plants. You get the number of rows, plants per row and the total for a square grid or a staggered triangular layout. Spacing values you find on seed packets and plant tags are typical figures, so adjust them for your variety. After switching units, re-enter your measurements.
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Formula
Work in the spacing unit (inches or centimetres). Let L be the bed length, W the width and s the spacing.
- Square grid:
rows = floor(W / s),plants per row = floor(L / s),total = rows x plants per row - Triangular offset: row pitch
p = s x 0.8660254,rows = floor((W - s) / p) + 1. Even rows holdfloor(L / s)plants; the shifted rows holdfloor(L / s - 0.5). - Density:
total / bed area
Worked example
An 8 ft by 4 ft bed (96 in by 48 in) with 12 in spacing:
- Square grid: 96 / 12 = 8 plants per row, 48 / 12 = 4 rows, so 32 plants.
- Triangular: pitch = 12 x 0.866 = 10.39 in, rows = floor(36 / 10.39) + 1 = 4. Rows 1 and 3 hold 8, rows 2 and 4 hold floor(8 - 0.5) = 7, so 8 + 7 + 8 + 7 = 30 plants.
At 24 in spacing the same bed holds 4 plants per row in 2 rows, so 8 plants (0.25 per square foot).
When to use it
Use it to turn a spacing from a seed packet into a plant count before you shop. It suits raised beds, borders and vegetable rows. Typical spacings are about 4 inches for radishes, 12 inches for lettuce and kale and 18 to 24 inches for tomatoes and squash, but they vary with variety.
Common mistakes
- Entering the bed in inches when the unit is set to feet.
- Using the spacing between rows when the packet gives the spacing within a row.
- Packing plants at the minimum spacing and forgetting they grow.
How it differs from nearby calculators
The seed quantity calculator turns a plant count into seeds to buy, the vegetable garden planner counts how many beds a crop list needs, and the garden bed area calculator measures the bed itself. This page counts the plants a given bed holds at a given spacing.
Frequently asked questions
How many plants fit in an 8 by 4 foot bed?
At 12 inch spacing in a square grid, an 8 by 4 foot bed holds 8 plants per row in 4 rows, which is 32 plants. A staggered triangular layout at the same spacing fits 4 rows alternating 8 and 7 plants, so 30.
What is the difference between square and triangular spacing?
A square grid puts plants at the corners of squares. A triangular layout shifts every second row by half a spacing, so rows sit 0.866 times the spacing apart instead of 1 times. That packs plants a little closer, about 15 percent more per area in a large bed, without any plant being nearer than the chosen spacing.
How does the calculator treat the bed edges?
Each plant is given a cell as wide as the spacing, so the first plants sit half a spacing from the edge. A 10 foot bed at 12 inches holds 10 plants per row. If the spacing is wider than the bed, the answer is zero.
What spacing should I use for my plants?
Use the spacing on your seed packet or plant tag. Typical values are about 4 inches for radishes, 12 inches for lettuce and kale, and 18 to 24 inches for tomatoes and squash, but they vary with variety and growing conditions. These are typical values, not guarantees.
How many tomato plants fit in a 4x8 raised bed?
At a typical 24 inch spacing a 8 by 4 foot bed holds 4 plants per row in 2 rows, which is 8 plants, or 0.25 plants per square foot. Check the spacing recommended for your variety.
How many plants per square foot at 6 inch spacing?
A square grid at 6 inch spacing gives 2 plants per foot in each direction, so 4 plants per square foot. A 4 by 4 foot bed holds 8 rows of 8, which is 64 plants.
How many lettuce plants fit in a 4x8 bed at 8 inch spacing?
Eight inches into 96 inches is 12 plants per row, and into 48 inches is 6 rows. That gives 72 plants, or 2.25 plants per square foot. Typical lettuce spacing is about 6 to 12 inches.