Row Spacing in Inches: Imperial Rows Per Bed

Row spacing in inches is the distance in inches between one row and the next row in a garden bed, and it decides how many rows fit across the bed width. This blog gives imperial row tables only, with rows and total row length for named bed widths and named spacings. Metric tables are in the companion blog.

What row spacing in inches means

Row spacing is the distance between the centres of two rows that run side by side along the bed. The calculator works with bed width, bed length, row spacing or row count, and an edge margin, which is the distance from each bed edge to the nearest row. Total row length equals rows times bed length.

The page formula step by step

Work in inches for bed width, spacing, and margin, and in feet for bed length. Do not mix units inside one sum.

Step 1: usable width equals bed width minus 2 times margin. With a 6 in margin at each edge, a 4 ft bed gives 48 minus 12, which is 36 in.

Step 2: rows equals floor of usable width divided by spacing, plus 1. Floor means divide, then drop any fraction, because a part row does not exist. The first and last rows sit one margin in from the edges, so the count is one more than the whole spacings that fit.

Step 3: total row length equals rows times bed length. A 10 ft bed with 4 rows gives 40 ft.

Worked example: a 4 ft bed at 12 in spacing

The page imperial example uses a 4 ft bed with 6 in margins and 12 in spacing, and it fits 4 rows. A 4 ft bed is 48 in wide. Usable width equals 48 minus 2 times 6, which is 36 in. Rows equals floor of 36 divided by 12, plus 1, which is 3 plus 1, which is 4. Without the plus 1, the sum would give 3 rows, because it would miss the last row. The 4 rows stand 12 in apart, with a 6 in margin at each edge. Total row length equals 4 times 10, which is 40 ft on a 10 ft bed.

The Row Spacing Calculator gives the same result with those entries, and it also lets you set the number of rows instead of the spacing.

Table 1: rows by bed width at 12 in spacing

Table 1 keeps the spacing at 12 in and the margin at 6 in, and changes only the bed width. Every bed is 10 ft long, so total row length equals rows times 10.

Bed width	Usable width	Rows	Total row length
2 ft	12 in	2	20 ft
3 ft	24 in	3	30 ft
4 ft	36 in	4	40 ft
5 ft	48 in	5	50 ft
6 ft	60 in	6	60 ft
8 ft	84 in	8	80 ft
10 ft	108 in	10	100 ft

A 2 ft bed gives 2 rows and 20 ft of row, and a 10 ft bed gives 10 rows and 100 ft of row. At 12 in spacing, each extra foot of bed width adds one row and 10 ft of row length.

Table 2: rows by spacing on the standard 4 ft bed

Table 2 keeps the bed at 4 ft wide and 10 ft long, with the margin fixed at 6 in, and changes only the row spacing. Usable width stays at 36 in.

Row spacing	Usable width	Rows	Total row length
12 in	36 in	4	40 ft
18 in	36 in	3	30 ft
24 in	36 in	2	20 ft
30 in	36 in	2	20 ft
36 in	36 in	2	20 ft

At 12 in spacing, rows are 4 and total row length is 40 ft. At 18 in spacing, rows are 3 and total row length is 30 ft. At 24 in spacing, rows are 2 and total row length is 20 ft. At 30 in spacing, the floor step drops the spare 6 in, so rows stay at 2. At 36 in spacing, rows are still 2.

Spacing for a set number of rows on the 4 ft bed

The calculator has a second mode. You can set the number of rows and let the calculator find the spacing. The formula is spacing equals usable width divided by rows minus 1, and usable width on the standard 4 ft bed with a 6 in margin is 36 in.

For 2 rows, spacing is 36 in. For 3 rows, spacing is 18 in. For 4 rows, spacing is 12 in. For 5 rows, spacing is 9 in. For 6 rows, spacing is 7.2 in. For 8 rows, spacing is 5.1 in, shown to one decimal place, because 36 divided by 7 is 5.143 in.

Spacing for 1 row cannot be worked out from this formula, because rows minus 1 is zero. One row is the single centre row case.

How to use the calculator

The page gives five steps. The calculator opens with defaults of 4 ft bed width, 10 ft bed length, 12 in spacing, 4 rows, and a 6 in margin. First, enter bed width and length. Second, choose to set spacing or number of rows. Third, enter the spacing or the row count. Fourth, set a margin from each edge, often half the row spacing. Fifth, mark rows with string before sowing.

The half spacing margin rule

Half the row spacing is a natural edge margin, so outer plants get the same room as inner plants. At 12 in spacing, half the spacing is 6 in, which is the page default margin and the margin used in both tables in this blog.

The half spacing rule and the fixed margin rule can give different answers, so always state which rule you used. This blog uses the fixed 6 in margin, and at 12 in spacing the two rules agree. At 18 in spacing they would not agree, because half of 18 in is 9 in. The page allows a margin of 0, but its guidance warns that plants right at the edge dry out and spill onto paths. A margin must stay below half the bed width.

Row spacing by crop size

The page FAQ gives row spacing by crop size in two bands. Small crops such as carrots and lettuce use 30 cm, which is 12 in. Larger crops use 45 to 90 cm, which is 18 to 36 in.

On the standard 4 ft bed, the small crop spacing of 12 in gives 4 rows and 40 ft of row. The larger crop band starts at 18 in, which gives 3 rows and 30 ft of row, and runs to 36 in, which gives 2 rows and 20 ft of row. The crop figures are starting points to edit, not universal constants.

Do not read the metric band as an exact match for the imperial band. The page gives 30 cm for small crops and 12 in for the same band, but 12 in is 30.48 cm, not 30 cm. A 6 in margin is 15.24 cm, not 15 cm. Also, 30 cm is 11.81 in, not 12 in, and 15 cm is 5.91 in, not 6 in. Never treat this imperial table as an exact metric conversion. Work the metric sum separately in the companion blog.

What the calculator does not give

The calculator gives rows, spacing, and total row length only, from bed width, bed length, row spacing or row count, and an edge margin. It gives no plants per row, no plants per bed, no density, no seeds, no yield, and no cost.

If you need plants per row, use a calculator that works from a spacing along the row as well as a spacing between rows. The Crop Spacing Calculator works from two spacings. The Plant Spacing Calculator works from a single spacing. The Plants per Square Foot Calculator gives plants per square foot, and the Garden Bed and Path Layout Calculator gives bed and path layout.

The page rules in one place

Rows often run north to south, because it gives both sides of the row even sun through the day. Raised beds do not always need rows. Paths between beds are not included in any figure in this blog. Direct sown rows can be closer than transplant rows.

Frequently asked questions

Q: What is row spacing in inches?
A: Row spacing in inches is the distance in inches between one row and the next row in a garden bed, and it decides how many rows fit across the bed width.

Q: How many rows fit a 4 ft bed at 12 in spacing?
A: 4 rows fit a 4 ft bed at 12 in spacing with a 6 in margin, with a usable width of 36 in and a total row length of 40 ft on a 10 ft bed.

Q: How do I work out total row length in feet?
A: Total row length equals rows times bed length, so 4 rows on a 10 ft bed gives 40 ft of row to sow and mark out.

Q: What spacing do I need for 5 rows on a 4 ft bed?
A: 9 in spacing, from usable width 36 in divided by 5 minus 1, which is 36 divided by 4.

Q: How far apart should vegetable rows be?
A: 12 in for small crops such as carrots and lettuce, and 18 to 36 in for larger crops, from the page FAQ.

Q: Should rows run north to south?
A: Often yes, because it gives both sides of the row even sun through the day, from the page FAQ.