Guide

Square-foot planting chart: how many plants actually fit per square

The footprint of the Vertical Grow System is nine one-foot squares. Square-foot gardening has a specific rule for how many plants go in each one, and it isn't always one.

By Moses Emmanuel · Reviewed by Romain Lefebvre

The spacing rule

Square-foot gardening is a method the retired engineer Mel Bartholomew developed and published in 1981, built around dividing a bed into one-foot squares instead of planting in rows. It sorts vegetables into four size classes, and each class gets a fixed number of plants per square:

• Extra-large: 1 per square. Cabbage, broccoli, cauliflower, peppers.
• Large: 4 per square. Leaf lettuce heads, Swiss chard, basil, parsley.
• Medium: 9 per square. Spinach, beets, bush beans, bush peas.
• Small: 16 per square. Radishes, carrots, onions.

the four spacing classes

This is different from the seed-packet spacing on most commercial seed bags, which is written for row gardening and wastes space in a square bed. The square-foot count assumes plants touching their neighbors at maturity, which works because a raised bed's soil isn't compacted by foot traffic the way row-garden soil is.

Square foot gardening chart, crop by crop

The four-class shorthand above is the popularized version. County extension course notes taken from a class Bartholomew taught in person break the same method down crop by crop instead of by size bucket, and a few land in a different spot than the four-class summary suggests: basil and parsley come out at 4 per square there, not 9, while beets and garlic come out at 9, not 4 or 16. Neither number is wrong, since spacing charts vary a little by source and by how tightly you're willing to crowd a given variety. Still, crop-specific counts are the ones to use if the four-class shorthand and a seed packet disagree. Lettuce and other greens have their own page, because heading and leaf lettuce get different counts, and so do herbs. The table below puts every crop from those notes in one place, with the spacing each count works out to.

• Broccoli
• Brussels sprouts
• Cabbage
• Cauliflower
• Kale
• Collards
• Butterhead and crisphead lettuce
• Peppers
• Eggplant
• Tomatoes
• Potatoes
• Corn
• Okra
• Cucumbers
• Leaf lettuce
• Swiss chard
• Bok choy
• Basil
• Parsley
• Cilantro
• Oregano
• Mint
• Strawberries
• Soybeans
• Fava beans
• Green (string) beans
• Spinach
• Beets
• Turnips
• Peas
• Garlic
• Carrots
• Radishes
• Green onions
• Small bulb onions
• Chives

Print this chart The print version drops the photos and menus and keeps only the table, sized for one letter or A4 page.

Square foot garden calculator

Enter the inside size of the bed and pick a crop. The calculator counts whole one-foot squares and multiplies by the crop's count from the chart. For a crop that isn't listed, choose the last option and type the spacing from the seed packet.

How many plants fit a whole bed

The same counts across the bed sizes people usually build. A 4 by 4 ft frame is the size the UW-Extension notes suggest for a first bed, and 2 by 2 ft is the smallest they mention. The 3 by 3 ft column is one tier of the Vertical Grow System.

Those are full beds of one crop. In a mixed bed each crop gets a few squares, so multiply its count per square by the number of squares it gets, which is the sum the calculator above does. The notes also say to plant only as much of a crop as you will eat, which usually means far fewer squares of radishes than the table allows.

Applying it to a 3-by-3-foot, 4-tier frame

The Vertical Grow System's footprint is nine squares. With four tiers, that's nine squares repeated four times, not thirty-six independent squares stacked freely: each tier is still one 3-by-3 layer, and what you plant in it depends on how much light that tier gets.

At those counts, a fully planted top tier holds 9 lettuces, the upper-mid tier holds up to 81 spinach or pea plants, the lower-mid tier holds 36 strawberry, basil, or parsley plants, and the radish tier holds up to 144. Most people plant fewer than the maximum, especially on the herb and radish tiers, to leave room to harvest without disturbing neighboring roots. Counts are only half the question, since whether two different crops can share a square depends on root depth, water demand, and height rather than on the counts, which is what our companion planting chart works through.

Why not just say "one crop per square"

Treating every square as a single planting slot is the easiest way to start, and it's a reasonable default for a first season. It undercounts what the frame can actually hold once you're comfortable spacing smaller plants closer together, which is the entire point of the square-foot method over row planting.

Planning by harvest date and light

The count tells you how many plants fit. Two other numbers decide which crops share the frame in the same season. Radishes are ready in about a month, while cabbage and peppers hold their squares for most of the summer, so the days to maturity chart helps you plan a second sowing into the squares that empty early. Light decides the tier: fruiting crops like tomatoes and peppers need the most sun, and the sunlight requirements chart sorts every crop above by hours of direct light.

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