Free plant spacing calculator
Set your bed size, your plant spacing, and a square or triangular layout — and see exactly how many plants fit, updated live, as you type.
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Estimates only, based on the bed size and spacing you enter. Allow extra for edges and walkways.
Results are estimates. Consult a professional.
How the plant spacing calculator works
Plant spacing is the centre-to-centre distance between one plant and its neighbours. The calculator takes that single distance, plus your bed length and width, and works out how many plants fit. It divides the bed length by the spacing to get plants per row, divides the bed width by the row-to-row distance to get the number of rows, then multiplies the two. The layout you pick changes only the row-to-row distance.
One spacing value drives everything. That keeps the tool simple: read the recommended spacing off the seed packet or a spacing chart, type it once, and the layout toggle does the rest. If you would rather set a separate in-row and row-to-row distance, the garden plot planner below handles that two-number case instead.
Square vs triangular spacing: which fits more plants
Most spacing charts assume a square grid. A square grid wastes space. Line plants up in straight rows and columns and the gaps on the diagonal are wider than the gaps along the rows — room you paid for in soil and never plant.
Triangular spacing closes that gap. Offset every other row by half a spacing and each plant sits in the centre of a hexagon, the same minimum distance from all six neighbours. The plants are no closer together. The rows simply nest, so they stack tighter from front to back.
Where the 15% comes from
Staggering the rows drops the row-to-row distance to spacing × 0.866. Since 1 ÷ 0.866 ≈ 1.155, you fit about 15% more rows — and therefore about 15% more plants — in the same bed at the same spacing. The gain is a property of the geometry, not a fudge factor. On small beds with wide spacing the rounding can erase it, so the calculator shows the real count for your exact bed rather than a flat 15%.
| Layout | Row-to-row distance | Best for |
|---|---|---|
| Square (grid) | = plant spacing | Quick to mark out; easy to hoe and harvest in straight lines |
| Triangular (staggered) | = spacing × 0.866 | Maximum plants per bed; dense ground cover; raised beds |
Both layouts hold the same minimum distance between neighbouring plants. Triangular only changes how the rows nest.
A worked example: square vs triangular in one bed
Priya has a square raised bed, 96 in × 96 in (8 ft each way), and wants marigolds at the recommended 12-inch spacing. She runs the bed both ways to see how many plants she needs to buy.
Step 1 — Count a square layout
Plants per row: 96 ÷ 12 = 8. Rows, at the full 12-inch row spacing: 96 ÷ 12 = 8. Total: 8 × 8 = 64 plants.
Step 2 — Shrink the row spacing for triangular
Triangular row spacing is 12 × 0.866 = 10.39 in. Plants per row is unchanged at 8 (the spacing along each row is still 12 in).
Step 3 — Count the triangular layout
Rows now: 96 ÷ 10.39 = 9.24, rounded down to 9 rows. Total: 8 × 9 = 72 plants.
Plant spacing chart for common vegetables and flowers
If you do not have a seed packet handy, this chart gives a typical centre-to-centre spacing for popular crops. Use the in-bed spacing for an intensive raised bed; traditional row gardens often leave wider walking rows between them.
| Plant | Spacing (in) | Spacing (cm) |
|---|---|---|
| Lettuce / salad greens | 6–12 | 15–30 |
| Carrots, radishes, beets | 3–4 | 8–10 |
| Bush beans | 4–6 | 10–15 |
| Peppers | 12–18 | 30–45 |
| Tomatoes (staked) | 18–24 | 45–60 |
| Tomatoes (caged) | 30–36 | 75–90 |
| Squash / cucumber | 18–24 | 45–60 |
| Marigolds / bedding flowers | 8–12 | 20–30 |
Spacing ranges follow the Utah State University and Colorado State University Extension vegetable guides and RHS sowing advice. Use the wider end for full-size plants and the tighter end for an intensive raised-bed planting.
For a bed where you want a different distance along the row than between rows — staked tomatoes are the classic case — plan it with the garden plot planner, which takes both numbers.
Why plant spacing matters for yield and disease
Spacing is not fussiness. Crowd plants and they compete for the same water, light and nutrients, and every one of them grows smaller for it. Give them room and each builds a stronger root system and carries a fuller crop.
Airflow and disease
The bigger reason is air. Plants packed too tightly trap humidity, and leaves that stay wet after rain or watering invite fungal and bacterial disease. Adequate spacing lets foliage dry, and the gap between plants slows a pathogen jumping from a sick plant to a healthy one by touch or splashing water.
Spacing that promotes air circulation helps foliage dry after rain or irrigation and limits how easily pathogens spread between neighbouring plants — a core part of integrated disease management, per the Alabama Cooperative Extension System.When to bend the rules
Tighter-than-chart spacing has its place. Intensive and square-foot beds run plants close on purpose to shade out weeds and lift yield per square foot, accepting more watering and feeding in return. Plant loose in a humid, disease-prone climate; you can plant tighter in a dry, breezy one. The chart is a starting point, not a law.
How to measure and mark out your spacing
The calculator gives the counts; marking the bed turns them into evenly spaced holes. A few minutes with a tape and string saves a wonky bed you cannot un-plant.
- Measure the bed. Record the planting length and width inside the frame, not the outside of the timber. Subtract any edge you want to keep clear.
- Pick the spacing. Read it off the seed packet or the chart above, and choose square or triangular to match how dense you want the bed.
- Mark the first row. Run a string along one long edge, then mark the plant spacing along it with a tape or a notched stick cut to the spacing.
- Set the row gap. Measure in by the row spacing the calculator gives — the full spacing for square, the ×0.866 figure for triangular — and run the next string.
- Offset for triangular. On every second row, start half a spacing in from the edge so the plants nest between the row in front. Square layouts skip this step.
Plant spacing definitions
How accurate is this plant spacing calculator?
The geometry is exact. For your bed and spacing, the plant-per-row and row counts are the precise whole numbers that fit, and the triangular row spacing uses the exact 0.866 factor rather than a rounded one. Change any input and the count updates to the plant.
The judgement is yours. The calculator fills the whole bed edge to edge; in practice you may want a clear margin around the rim, a path down the middle, or a half-plant of breathing room near a fence. It also assumes one spacing for the whole bed, so mixed plantings need a run per crop. Treat the total as the ceiling — the most plants that fit at that spacing — and trim it to suit how you tend the bed. When a plant sits between two chart values, the wider spacing is the safer bet for airflow and final size.
Frequently asked questions about the free plant spacing calculator
About this Plant Spacing calculator
This plant spacing calculator runs entirely in your browser. Nothing you type is sent anywhere or saved — change the bed size, the spacing, or the layout and the plant count updates instantly on your device.
It is one of our free home & garden calculators. Browse the full set in the calculators library to plan the rest of your beds, borders, and yard.