Plant Spacing Calculator

1. Enter the bed area in square feet (length times width).
2. Enter the plant spacing in inches, center to center, from the plant tag.
3. Pick a layout: a square grid or a tighter triangular stagger.
4. Add extra for edges if you want spares, and read the plant count.

Here is what each result line means:

Prepping the bed with soil first? Size it with the topsoil calculator.

A plant spacing calculator turns a bed area and a spacing into the number of plants needed to fill it. It works for ground covers, annuals, perennials, shrubs and bulbs, in either a square grid or a staggered triangular layout.

The spacing is the center-to-center distance between neighboring plants, set by the mature spread on the plant tag. Each plant occupies a patch of ground; the bed area divided by that patch is the plant count.

Working out beds and borders? Pair this with the landscape fabric calculator.

In a square grid each plant sits at the center of a square whose side is the spacing, so it occupies spacing squared. The bed area divided by that gives the count. A triangular layout staggers the rows so plants pack closer.

1. Convert spacing to feet: spacing in inches divided by 12.
2. Square grid: plants = area divided by spacing in feet squared.
3. Triangular: divide again by 0.866, which fits about 15 percent more plants.

The 0.866 factor is the height of an equilateral triangle (the square root of 3, over 2). It is exact geometry, not a rule of thumb, and always rounds the plant count up.

A 100 sq ft bed at 12 in spacing.

Calculation: 12 inches is 1 foot, so each plant occupies 1 square foot. Square grid = 100 / 1 = 100 plants. Triangular = 100 / 0.866 = 115.5, rounded up to 116 plants.

A 200 sq ft bed at 18 in is 200 / 2.25 = 89 in a grid; at a triangular layout, about 103.

Spacing

The dominant factor, and it is squared. Halving the spacing roughly quadruples the plant count, so 6-inch spacing needs four times as many plants as 12-inch.

Layout

A triangular stagger fits about 15 percent more plants than a square grid at the same spacing, and gives fuller coverage with no lined-up gaps.

Mature Spread

Set the spacing from the mature spread on the tag, not a round number. Too wide leaves bare soil; too tight crowds the plants as they grow.

Bed Shape and Edges

Irregular beds and borders lose a few plants at the edges, so add a small extra for odd shapes and replacements.

Fill Speed

Closer spacing fills in faster for an instant look but costs more; wider spacing is cheaper and fills in over a season or two.

Plants per 100 square feet in a square grid, by spacing.

A triangular layout fits about 15 percent more than each figure above. Closer spacing costs far more in plants but fills in sooner; wider spacing saves money and fills over time. Match the spacing to the plant and your budget.

Ground Covers

Figure how many plugs or pots fill a bank or bed at the recommended spacing.

Annual and Perennial Beds

Plan a mass planting so it reads full without crowding.

Hedges and Screens

Space shrubs along a run for a solid screen at maturity.

Vegetable and Bulb Beds

Lay out a productive bed or a drift of bulbs on a grid or stagger.

Budgeting a Planting

Turn a bed into a plant count and compare grid against triangular before you buy.

1. Spacing Edge to Edge

Spacing is center to center. Measuring between the outsides of plants spaces them too far apart.

2. Ignoring Mature Spread

Planting to the pot size, not the mature spread, crowds the bed in a couple of seasons. Use the tag spacing.

3. Forgetting the Squared Effect

Halving the spacing nearly quadruples the count and cost. Small spacing changes move the number a lot.

4. No Edge Allowance

An irregular bed loses plants at the edges. Add a small extra for odd shapes and replacements.

5. Grid When Triangular Is Better

A square grid leaves lined-up gaps. A triangular stagger covers more fully and fits more plants.

6. One Spacing for Every Plant

Different species have different spreads. Run the calculator per plant type, not once for a mixed bed.

The calculator estimates plant count from the bed area, spacing, layout and edge extra.

Divide the bed area by the space each plant occupies. At 12-inch spacing each plant takes 1 square foot, so a 100 square foot bed needs 100 plants in a grid, or 116 triangular.

Plants equal the area divided by the spacing in feet squared for a square grid. For a triangular layout, divide again by 0.866 to fit about 15 percent more.

About 15.5 percent more plants than a square grid at the same spacing, because staggered rows sit closer together. It also gives fuller coverage with no lined-up gaps.

Yes. The spacing is the distance between the centers of neighboring plants, not the gap between their edges. Set it from the mature spread on the tag.

At 6-inch spacing, 4 per square foot; at 12 inches, 1; at 18 inches, about 0.44; at 24 inches, 0.25, for a square grid. Triangular fits about 15 percent more.

Use the recommended spacing on the tag, often 6 to 18 inches. Closer spacing fills in faster but costs more; a triangular layout covers most fully.

Add about 10 to 15 percent for edge losses, replacements and an irregular bed. The base count is the maximum that fits on flat, regular ground.

Because spacing is squared. Halving it roughly quadruples the count, so 6-inch spacing needs about four times as many plants as 12-inch.

Yes. Tighter spacing gives an instant, full look but costs more in plants; wider spacing is cheaper and closes over a season or two.

No. The calculator runs entirely in your browser and nothing is stored or sent.

• University of Missouri / Virginia Tech – Ground Cover Spacing (Area covered and plants per 100 by spacing.)
• Lurvey – Planting Information Sheet (Square feet per plant and plants per sq ft.)
• Sunset – Ground Cover Spacing Chart (Spacing guidance and coverage.)