Plant Spacing Calculator

How many plants do I need?

Divide the bed's area by the space each plant takes up. In a square grid, each plant takes spacing × spacing. In offset (triangular) rows, it takes a bit less. A 10 × 6 ft bed at 12 inch spacing needs 60 plants in a grid and 70 in offset rows.

Offset rows use spacing² × 0.866 per plant, so they fit about 15% more plants in the same bed. Illinois Extension recommends a staggered or diamond pattern for ground covers.

How to use the plant spacing calculator

The plant spacing calculator turns a bed size and a spacing into a plant count. The "How we calculated this" panel shows each step, and the PDF report keeps the numbers for your nursery order.

Step 1: Enter the bed size

Type the bed dimensions, the length and width in feet, or the square feet if you know them. For curved beds, measure the shape in the square footage calculator first.

Step 2: Enter the spacing from the plant tag

Spacing is measured from the center of one plant to the center of the next. The tag or catalog gives it for each variety, based on the mature width.

Step 3: Pick a square grid or offset rows

Square grids are easy to lay out. Offset rows pack more plants into the same bed and cover the soil sooner, which suits ground covers and mass plantings.

Step 4: Add price and flats

Enter the price per plant and the plants per flat to see the cost and the number of flats to order.

Plants per square foot at common spacings

Plants per square foot and per 100 sq ft, for a square grid and for offset rows.

The grid column matches the Illinois Extension ground cover table: 400 plants per 100 sq ft at 6 inches, 100 at 12 inches and 45 at 18 inches.

Square vs triangular spacing

A square grid puts each plant at the corner of a square, with the same gap between rows and within rows. Triangular spacing shifts every second row by half a space, so each plant has six equal neighbors.

Kentucky State University describes this hexagonal pattern: every plant is the same distance from its six nearest neighbors. The row gap is spacing × 0.866, the height of an equilateral triangle.

Why the area per plant matters

The area a plant gets grows with the square of the spacing. Kentucky State University notes that plants 13 inches apart in a hexagonal lattice each have about a square foot, while plants 26 inches apart each get four square feet. Doubling the spacing quarters the plant count.

Ground cover, perennials and shrubs

Illinois Extension says to space faster growing ground covers further apart than slow growing ones. Slow spreaders go closer, which costs more but covers the soil sooner.

For perennials and shrubs, use the mature width on the tag. A shrub planted at its mature width touches its neighbors once it is grown, and gives a continuous mass.

Plant spacing for vegetables and square foot gardening

Square foot gardening divides a bed into 1 × 1 ft squares and plants a set number in each, based on the crop's size. The Old Farmer's Almanac lists these counts per square. Enter the spacing from the seed packet and the calculator gives the same numbers.

The Almanac says any raised bed 4 feet wide works, because you can reach every square without stepping into the bed. For soil volume, use the raised bed soil calculator.

How many plants for a hedge?

A hedge is a single row, so count along its length. Plants per foot is 12 divided by the spacing in inches, and you add one for the plant at the end.

A 30 ft hedge at 36 inch spacing takes 30 × 12 ÷ 36 + 1 = 11 plants. For a thicker hedge, plant two staggered rows with a row gap of spacing × 0.866.

Why plant spacing matters

The Old Farmer's Almanac says correct spacing keeps a bed tidy and reduces competition for nutrients. Plants that are too close compete for water and root space, and their shade and dense foliage dry slowly, which suits pests and fungal disease.

Plants set too far apart leave bare soil showing for longer, and in the first year you pay for it in weeding.

Allow each plant room for its roots and its fully grown width, and plan the pattern around that recommended spacing. It is a balance between cost and speed, so use this resource to try a few spacings before you order flowers, perennials or shrubs.

Common plant spacing mistakes

• Using the nursery pot size. Space by the mature width on the tag, not the size of the pot.
• Measuring edge to edge. Spacing is center to center.
• Ignoring the pattern. Offset rows at the same spacing take about 15% more plants than a grid, so pick the pattern before you order.
• Buying exactly the count. Add a few spares for first-season losses.

Before you order plants

Measure the bed, take the spacing from the tag, pick a square grid or offset rows, and let the plant spacing calculator give the count. Add a few spares, compare the price per plant with the price per flat, and download the PDF report for your nursery.

Frequently asked questions