What does this planner do?
Square foot gardening divides a raised bed into a grid of 1 foot squares and plants each square at a fixed density. This planner shows you that grid. Enter the bed length and width, pick a crop, and it counts the whole squares, the plants per square, and the total plants the bed can hold.
The result doubles as a planting guide: a square holding 16 carrots means thinning to one plant every 3 inches, while a square holding 1 cabbage gets the full 12 inches.
How the per-square density works
The densities come from the spacing between plants. A crop spaced 3 inches apart fits 16 in a square foot (4 by 4 plants). Six inch spacing fits 4. Four inch spacing fits 9. Twelve inch spacing gives 1 plant per square.
The crop list in the tool assigns each plant its conventional square foot density:
| Per square | Spacing | Crops |
|---|---|---|
| 1 | 12 inches | Tomato, pepper, eggplant, broccoli, cabbage, cauliflower, kale, okra, cucumber, zucchini |
| 4 | 6 inches | Lettuce, chard, celery, basil, parsley, arugula, marigold |
| 9 | 4 inches | Bush beans, peas, beets, spinach, garlic, parsnips, leeks |
| 16 | 3 inches | Carrots, radishes, small onions |
Very large plants are the exception. A vining squash or melon can occupy a square while its vines run outside the grid, and trellised cucumbers and peas grow upward from a single square on the bed's north edge.
Setting up the grid
The grid is not optional decoration in this system; it is what makes the planting densities work. String, thin lath, or bamboo laid across the bed frame marks the squares and keeps spacing honest at sowing time. Without it, plantings drift toward row spacing and the dense packing that makes the method productive disappears.
Bed width matters more than length. Keep beds to 4 feet or narrower so you can reach every square from the sides without stepping in. Foot traffic in the bed compacts soil and defeats the point of the loose, deep planting mix.
Worked examples
A 4 by 4 salad bed
Sixteen squares of lettuce at 4 plants per square holds 64 lettuce plants, far more than most households can eat at once. A realistic plan dedicates 4 squares to lettuce (16 plants), 4 to carrots (64 plants at 16 per square), 4 to spinach (36 plants), and keeps 4 for a tomato and three basil squares.
A 4 by 8 tomato bed
Thirty-two squares planted entirely in tomatoes would hold 32 plants, which is more than the light and air can support in practice. Putting tomatoes along the back row of 8 squares, peppers in the middle 8, and basil and marigolds in the front 16 uses the grid without inviting a disease canopy.
Common mistakes
Skipping the grid
Densities assume plants are centered evenly in each square. Freestyle sowing in a divided bed tends to overplant the open middle and underplant the edges.
Planting every square the same week
A bed that hits maturity all at once feeds you for two weeks, not a season. Stagger a few squares of fast crops like radish and lettuce every week or two instead.
Ignoring the north edge rule
Tall and trellised crops belong on the north side of the bed. A row of tomatoes planted along the south edge shades every square behind it for the whole afternoon.
Crowding large plants
One tomato per square is already tight. Two per square produces a tangled canopy that invites fungus and halves the harvest.
When this planner may not be the right choice
The grid suits raised beds and small intensively planted gardens. For in-ground rows, the plant spacing calculator handles row spacing that square foot planting does not use. Perennials, sprawling crops like pumpkins and sweet corn blocks, and orchard plantings need more room than a 1 foot grid describes.
Frequently asked questions
Why do some crops get a whole square? Density follows mature size: 16 small plants like carrots share a square, 4 medium ones like lettuce, and 1 large one like pepper. The 1, 4, 9, 16 scheme is the standard square foot spacing.
Can I grow tomatoes in a square foot bed? One plant per square works when the tomato is trained vertically on a trellis along the north edge, where it will not shade the rest of the bed. Untrained bush tomatoes want more room than a single square.
Do I need a physical grid? The grid is what makes the system work. It forces spacing discipline and keeps paths out of the bed, which is where the method's density comes from. A mental grid tends to dissolve by midsummer.
