gizmobench

Plant Spacing Calculator

Type the bed, the spacing you are planting at and how far in from the edge the outside plants sit, and this page lays the grid out and counts what actually fits, row by row, drawing a dot for every plant it counts while the count is small enough for a diagram to mean anything. A 12 by 4 foot bed at 12 inch spacing with a 6 inch setback takes 48 plants in 4 rows of 12, or 46 staggered, in 4 rows of 12 and 11. That is not what dividing the area gives, and the difference is the point: a 10 by 10 metre bed at 1 metre spacing holds 121 plants laid out with no setback and only 100 by area, because the division forgets the row that starts at the edge. Both figures are on the page, named as what they are, along with the arithmetic that produced each one. Square and triangular grids are one click apart, feet and metres one switch, and the spacing itself is yours to type: this page counts positions and has no view about what goes in them.

12 ft x 4 ft, one dot a plant
Working48 sq ft of bed
bed        12 ft x 4 ft
spacing    12 in
pattern    square
setback    6 in from each edge

rows       4   ·   per row 12
plants     48   (triangular: 46)
formula    along 11 ft: floor(11 / 1) + 1 = 12 a row · across 3 ft: floor(3 / 1) + 1 = 4 rows · 12 x 4 = 48
area check 48 under the area method, which divides 48 sq ft by 1 and ignores edges
Plants
48
Rows
4 of 12
Pattern
Square
Spacing
12 in
Bed given as
Length in ft
Width in ft
Spacing in in
Setback in in
Bed measured in

The setback is where most calculators quietly disagree with a tape measure: it is the distance from the bed edge to the first plant centre, and it is a field here rather than an assumption. Set it to half the spacing and the grid tiles evenly when two beds sit side by side; set it to 0 and the outside plants sit on the edge itself. Triangular spacing shifts every second row half a spacing along and brings the rows closer together, to 0.866 of the spacing, which is why it is about 15 per cent denser per square foot or square metre. Denser is not the same as more: in a real rectangle the edges decide the count, and the staggered case below comes out below the square one on the same bed, because the shifted rows lose at the ends what the closer rows gain. The working prints the other pattern's count beside your own, so the comparison is never guesswork. The spacing itself comes from you: a packet, a plan or a nursery label knows what you are planting, and this page does not.

  • 12 x 4 ft, 12 in, square6 in setback from each edge
    48 plants
  • The same bed, triangularsame spacing, rows shifted and closer
    46 plants
  • No setback, square gridoutside plants sit on the bed edge
    65 plants
Exact on the geometry, silent on the horticulture. Exact geometry on the bed and spacing you enter, counting whole plants that actually fit inside the edge setback rather than dividing areas. It is a spacing count and gives no advice about which plants suit a bed or a season. The working beside the diagram prints the formula it used, and the area method is shown next to it rather than instead of it, because that division is what other calculators return and the gap between the two is worth seeing.

Common questions

How many plants fit in a 4 by 8 foot raised bed?
At 12 inch spacing with the outside plants set 6 inches in from the edge, an 8 by 4 foot bed takes 32 plants, in 4 rows of 8. Drop the setback to 0 and the outside plants sit on the bed edge, which makes it 45, in 5 rows of 9. Switch the same bed to a staggered grid and it comes to 30, in 4 rows of 8 and 7: on a bed this narrow the shifted rows lose more at the ends than the closer rows gain, which is the kind of thing a diagram shows and a formula hides. Type your own numbers and the count follows them.
How do I calculate plant spacing myself?
Take the setback off both ends of each side to get the usable span, divide by the spacing, round down and add one, because a row has a plant at each end. A 12 by 4 foot bed with a 6 inch setback has 11 feet by 3 feet usable, so at 12 inch spacing that is floor(11 / 1) + 1 = 12 plants a row and floor(3 / 1) + 1 = 4 rows, which is 48. Widen the spacing to 18 inches on that same bed and it becomes 24, in 3 rows of 8. The other method, the one most calculators use, divides the bed area by the ground one plant takes: 48 square feet over 1 square foot is 48 here, but on a 10 by 10 metre bed at 1 metre spacing it gives 100 where the layout gives 121. This page prints both, with the working, so you can see which one your supplier is quoting.
Is triangular spacing better than square spacing?
It is denser per square metre and not always more plants in your bed. A staggered grid shifts every second row half a spacing along and puts the rows 0.866 of a spacing apart, so by area it fits about 15 per cent more: 115 plants in 100 square feet at 12 inch spacing against 100 on a square grid. In a real rectangle the edges decide it. A 10 by 10 metre bed at 1 metre spacing with no setback holds 126 staggered against 121 square, while the 12 by 4 foot bed at 12 inches with a 6 inch setback holds 46 staggered against 48 square. The page shows the other pattern's count next to the one you picked, so the comparison is one glance rather than two calculations.
What should I use for the edge setback?
The setback is the distance from the bed edge to the first plant centre, and it is a field here because it changes the answer more than anything except the spacing. Half the spacing is the usual choice, and it is what makes a grid tile evenly when beds sit side by side: at 12 inch spacing that is 6 inches. Set it to 0 and the outside plants sit on the edge itself, which on the 12 by 4 foot bed turns 48 plants into 65. Most calculators assume one of these without telling you, and that alone can account for the difference between two numbers you are trying to reconcile.
How far apart should the plants actually go?
That comes from what you are planting, and this page does not know what that is. A seed packet, a nursery label or a planting plan gives a spacing, and this page counts what that spacing fits in your bed. There is no species table here and no seasonal advice, on purpose: a spacing that is right for one variety in one soil is wrong for another, and a calculator that guessed would be inventing the most important number on the page. Type the figure you were given, in inches or centimetres, and the geometry is exact from there.
Can I use my bed area instead of its length and width?
Yes. Switch Bed given as to Area only and type the square feet or square metres, and the page answers with the area method: 100 square feet at 12 inch spacing is 100 plants square, or 115 staggered. It says so plainly rather than quietly rounding, because an area on its own has no edges, so there are no rows to place and no setback to apply. If you have a length and a width, use them: the laid out count is the one that matches what happens when you get to the bed with a tape measure.
Does it work in metres, and does the page keep my bed?
Both. The units switch takes the bed in feet or metres, with spacing and setback in inches or centimetres to match, and switching rewrites what you already typed instead of clearing it, using the exact definitions, so a foot becomes 0.3048 metres and back again to the digits you started with. A 10 by 10 metre bed at 100 centimetre spacing is 121 plants laid out, 126 staggered, and 100 under the area method. Your bed, spacing, setback, pattern and unit stay in your browser's own storage so the page opens where you left it. Nothing is uploaded, there is no account, and clearing your browser data clears it.

Exact geometry on the bed and spacing you enter, counting whole plants that actually fit inside the edge setback rather than dividing areas. It is a spacing count and gives no advice about which plants suit a bed or a season.