Plant Spacing Calculator

1. Enter your bed length and width in centimetres.
2. Enter the spacing between plants along a row.
3. Enter the spacing between rows.
4. Read the total plants, plants per row, number of rows and the density per square metre.

Plant spacing is the distance you leave between plants, and between rows, so each one has enough room to grow. It is one of the most important choices in a garden, because crowded plants compete for light, water and nutrients, while plants set too far apart waste bed space.

Seed packets and plant labels give a recommended spacing. This calculator turns that recommendation into a real plant count for your bed, so you buy the right number of seedlings and use the space well.

1. Divide the bed length by the in-row spacing and round down for plants per row.
2. Divide the bed width by the row spacing and round down for the number of rows.
3. Multiply the two for the total number of plants.
4. Divide the total by the bed area in square metres for density.

Rounding down means every plant has its full spacing, so the bed is never overcrowded at the edges.

You have a bed 300 centimetres long and 120 wide, and your crop wants 30 centimetres between plants and 40 between rows. Plants per row are 300 divided by 30, which is 10. Rows are 120 divided by 40, which is 3. That gives 30 plants in total, on a bed of 3.6 square metres, or about 8.3 plants per square metre. Widen the spacing to 45 centimetres and the count drops as each plant claims more room.

Recommended Spacing

The mature size of the crop sets the spacing; sprawling plants such as courgettes need far more room than lettuces.

Bed Dimensions

Longer and wider beds hold more plants, but odd sizes leave gaps that rounding down accounts for.

Row vs Grid Layout

Square or offset grids can fit more plants than widely separated rows, so closing the row spacing raises the count.

Access Paths

Leaving room to reach the middle of a bed reduces the plantable area, so measure only the space you will actually plant.

Typical spacings vary widely by plant, which is why the count changes so much.

Always check your seed packet, as varieties differ, but these ranges show how much spacing drives the final plant count.

Planning a Bed

Decide how many seedlings to raise or buy before the season starts.

Ordering Seeds and Plants

Match your order to the space so you do not over or under-buy.

Comparing Layouts

Test tighter or wider spacings to balance yield against plant health.

1. Planting Too Close

Crowded plants shade each other and invite disease, cutting yield despite the higher count.

2. Ignoring Mature Size

A tiny seedling needs the spacing of the full-grown plant, not the size it is on planting day.

3. Forgetting Paths

Counting the whole bed, including walkways you cannot reach across, overstates how many plants fit.

4. Mixing Up the Two Spacings

In-row and between-row spacing are often different; swapping them changes the layout and the count.

The grid maths is exact for evenly spaced rows and gives a dependable plant count. Real beds vary with edges, paths and offset planting.

Multiply the plants per row by the number of rows. In a 300 by 120 cm bed at 30 cm spacing and 40 cm rows, that is 10 times 3, or 30 plants.

Plant spacing is the gap between plants along a row; row spacing is the gap between one row and the next. They are often different.

Check the seed packet or plant label, which give a recommended distance based on the plant mature size. Lettuce needs about 20 cm, tomatoes about 45.

Offset, or triangular, spacing fits more plants into the same area. This tool uses a simple square grid, giving a slightly conservative count.

Rounding down guarantees every plant gets its full spacing, so the bed is not overcrowded at the ends of rows.

Not always. Beyond a point, crowding reduces the size and health of each plant, so total yield can fall even with more plants.

Measure only the area you will actually plant, leaving out any walkway you need to reach the middle of the bed.

Yes. Enter the inside dimensions of the container or raised bed and the same spacing rules apply.

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

• Plant spacing and density (Wikipedia).
• Gardening basics (Wikipedia).
• Intensive planting methods (Wikipedia).