Plants Per Acre: Imperial Crop Spacing Tables

Plants per acre tells you how many plants stand on one acre when spacing is even across the ground. One acre is 43,560 sq ft, so the figure comes from the ground area that one plant takes. This blog works it in imperial units only, for the 14 vegetable presets in the Crop Spacing Calculator.

What plants per acre means here

Plants per acre is a density, not a count for a bed. If every plant had the same rectangle of ground, with in row spacing on one side and between row spacing on the other, how many rectangles fit in one acre. Wider spacing gives fewer plants per acre. Closer spacing gives more. The figure says nothing about paths, headlands, or access lanes. It is for planted ground only.

A bed count rounds down to whole rows and whole plants, because a part row does not exist. A plants per acre figure divides the whole acre by the area for one plant, and rounds to the nearest whole plant. Use the bed count for a named bed. Use plants per acre to compare crops or work out a field total.

The method in full

Work in feet throughout. First, divide in row spacing in inches by 12 to get feet. Second, divide between row spacing in inches by 12 to get feet. Third, multiply the two feet figures to get sq ft per plant. Fourth, divide 43,560 by that area, and round to the nearest whole plant. In words, plants per acre equals 43,560 divided by in row feet times between row feet.

The Crop Spacing Calculator takes the same two spacings, plus a bed size, and gives plants per bed, rows, plants per row and a plan. The plants per acre figures here are not outputs from that calculator. They are arithmetic from its preset spacings.

Worked example: tomatoes at 24 by 36 in

Tomatoes use a preset of 24 in in row and 36 in between rows. The page also gives a wider range, 18 to 24 in in row with 30 to 36 in between rows. The preset sits at the wide end, so treat it as a starting point to edit for your variety and soil.

Work it step by step. 24 divided by 12 is 2 ft. 36 divided by 12 is 3 ft. 2 times 3 is 6 sq ft per plant. 43,560 divided by 6 is 7,260. Tomatoes at 24 by 36 in give 7,260 plants per acre.

Worked example: lettuce at 10 by 12 in

Lettuce uses a preset of 10 in in row and 12 in between rows. The page also gives a range for lettuce heads, 8 to 12 in apart, with closer spacing for cut and come again leaves. The preset of 10 in sits inside that range.

Work it step by step. 10 divided by 12 is 5 by 6 ft, which is 0.8333 ft. 12 divided by 12 is 1 ft. 5 by 6 times 1 is 5 by 6 sq ft. 43,560 times 6 divided by 5 is 52,272. Lettuce at 10 by 12 in gives 52,272 plants per acre. Keep the fraction through the working, and round only at the end.

The full plants per acre table

Read the table by crop name, then spacing, then density. The spacing column gives the preset in inches, in row first and between rows second. Peppers, cabbage and broccoli, and kale all use 18 by 24 in, so all three give 14,520 plants per acre. Spinach, beetroot, and onions all use 4 by 12 in, so all three give 130,680 plants per acre. Garlic uses 6 by 12 in and bush beans use 4 by 18 in, and both give 0.5 sq ft per plant, so both give 87,120 plants per acre.

Crop	In row by between rows	Plants per acre
Tomatoes	24 by 36 in	7,260
Peppers	18 by 24 in	14,520
Potatoes	12 by 30 in	17,424
Cabbage and broccoli	18 by 24 in	14,520
Kale	18 by 24 in	14,520
Lettuce	10 by 12 in	52,272
Spinach	4 by 12 in	130,680
Carrots	2 by 12 in	261,360
Beetroot	4 by 12 in	130,680
Onions	4 by 12 in	130,680
Garlic	6 by 12 in	87,120
Bush beans	4 by 18 in	87,120
Sweet corn	10 by 30 in	20,909
Squash and courgettes	36 by 48 in	3,630

Sweet corn is the one figure that is not whole before rounding. It uses 10 by 30 in, which is 5 by 6 ft by 2.5 ft, so area per plant is 2.0833 sq ft. 43,560 divided by 2.0833 is 20,908.8, shown as 20,909.

How to read the table

Check that the spacing in the table matches the spacing you plan to use. If you change the spacing, the table figure no longer applies. Spacing varies by variety. Compact and dwarf types need less room. Close spacing suits rich soil and good watering. Vining crops can be trained vertically to save space. The presets are starting points, not constants.

Carrots at 2 by 12 in give 261,360 plants per acre, which is 72 times the squash and courgettes figure of 3,630 at 36 by 48 in. For a small area, the Plants per Square Foot Calculator works the same area method at garden scale.

Field totals: scaling the table to a field size

Total plants equals plants per acre times area in acres. Find the figure for your crop, multiply it by the acres, and write the spacing beside the total.

Work the tomato example in full for 5 acres. Tomatoes at 24 by 36 in give 7,260 plants per acre. 7,260 times 5 is 36,300. A 5 acre field at that spacing holds 36,300 plants on planted ground only, with no paths, headlands, or access lanes taken out. If the field has paths or headlands, work the total from the planted acres, not the whole field.

The table below scales four crops across 1, 2, 5, and 10 acres.

Crop	Plants per acre	1 acre	2 acres	5 acres	10 acres
Tomatoes	7,260	7,260	14,520	36,300	72,600
Lettuce	52,272	52,272	104,544	261,360	522,720
Carrots	261,360	261,360	522,720	1,306,800	2,613,600
Squash and courgettes	3,630	3,630	7,260	18,150	36,300

Use the Garden Area Calculator to work out the area of a plot before you multiply. Measure the planted ground, not the whole plot.

Warning: these densities are arithmetic, not calculator outputs

The Crop Spacing Calculator gives plants per bed, rows, plants per row and a planting plan, from two spacings and a bed size. It gives no plants per acre figure and no plants per hectare figure. The table here is arithmetic from the preset spacings, not a calculator output. You cannot check it by entering an acre in the calculator, because it has no acre input and no density output. The table also uses the full acre with no edge margin and no rounding down to whole rows, while a bed count rounds down to whole rows.

The Plants per Acre Calculator is a different tool. It takes a spacing and a layout choice and gives plants per acre or per hectare and a total for your area. This table gives a density and a field total only. It gives no yield figure, no seed count, no cost, and no bag count. For row crops in a field, the Plant Population Calculator takes two spacings and gives a population figure and a total.

Warning: do not treat this as a metric per hectare table

The metric and imperial preset columns are rounded equivalents, not exact conversions. 24 in is 60.96 cm, not 60 cm, so metric and imperial tables from the two preset columns give slightly different densities. Do not present this table as equal to a metric plants per hectare table.

Sweet corn proves the point. Metric sweet corn gives 53,333 plants per hectare. Divide that figure by 2.47105, and the result is 21,583 plants per acre. That does not match the imperial figure here, which is 20,909 plants per acre. The gap is 674 plants per acre, and it comes from the rounded preset columns, not from an error in arithmetic.

Frequently asked questions

Q: How many plants per acre do tomatoes give at 24 by 36 in?

A: 7,260 plants per acre. 24 in is 2 ft, 36 in is 3 ft, and 43,560 divided by 6 is 7,260.

Q: How many plants per acre does lettuce give at 10 by 12 in?

A: 52,272 plants per acre. 10 in is 5 by 6 ft, 12 in is 1 ft, and 43,560 divided by 5 by 6 is 52,272.

Q: How do I work out plants per acre from spacing in inches?

A: Divide each spacing by 12 to get feet, multiply to get sq ft per plant, then divide 43,560 by that area.

Q: How many tomato plants do I need for 5 acres at 24 by 36 in?

A: 36,300 plants. 7,260 times 5 is 36,300.

Q: Why does sweet corn give 20,909 plants per acre here and not 21,583?

A: 20,909 is the imperial figure, from 10 by 30 in. 21,583 is 53,333 plants per hectare divided by 2.47105. The presets are rounded equivalents, so they do not match.

Q: Does the Crop Spacing Calculator give plants per acre?

A: No. It gives plants per bed, rows, plants per row and a plan. The plants per acre figures here are arithmetic from the presets, not calculator outputs.