Square Foot Planner
Plan a square foot bed: how many squares, and how many plants of a crop they hold.
Square foot gardening plans a bed as a grid of one foot squares, each square carrying a fixed count of its crop: 1 tomato, 4 lettuces, 9 bush beans, 16 carrots. This planner counts your bed’s squares, applies the per-crop density for the squares you allocate, and totals the plants and expected harvest, so a gridded bed can be planned square by square before a single string is stretched.
Densities follow the standard square foot method, which is deliberately tighter than row spacing: it assumes rich, deeply prepared soil and hand weeding. If your bed is ordinary, expect the top of the yield range rather than beyond it.
How square foot densities work
Density steps down with the crop’s mature size: 16 per square for 3 inch crops like carrots and radish, 9 for 4 to 5 inch crops (bush beans, beets, turnips), 4 for 6 inch crops (lettuce, spinach, onions), 2 for bulky 8 to 9 inch plants in some traditions (here folded to the spacing table), 1 per square for 12 inch crops, and 1 per 4 squares for the 24 inch sprawl of tomatoes and brassicas, more for squash. The planner derives each crop’s density from the same spacing table the rest of the site uses, so square foot and conventional plans agree on the plant’s true footprint.
Assumptions:
- Square foot soil is deep, rich and loose, and watering is by hand to the plant. Ordinary soil at these densities yields at the low end of the range.
- One crop per square is the method’s rule; mixed squares are the conventional planner’s job.
- Vertical crops (peas, beans, cucumbers on the north edge trellis) count their ground square only, which is the method’s great space trick and entirely legitimate.
Worked examples
1. A 4 x 4 bed (16 squares) in carrots. Four squares of carrots: 64 plants, a few pounds of roots from a sixth of the bed. The grid makes small crops countable, which is most of its charm.
2. A tomato in the same bed. One plant per 4 squares: a quarter of the bed for one plant, the honest price of a tomato even in intensive systems, and the reason trellising and pruning earn their keep.
3. A full salad rotation. Lettuce 4 per square, radish 16, spinach 4: the map turns over every few weeks, and the planner’s per-square counts are exactly what a succession notebook needs per sowing.
Density table
| Plants per square | Crops at this density |
|---|---|
| 16 | Carrots, radish |
| 9 | Bush beans, beets, turnips, peas (by spacing) |
| 4 | Lettuce, spinach, onions, garlic, strawberries |
| 1 | Peppers, kale, chard, celery, potatoes |
| 1 per 4 squares | Tomatoes, cabbage, broccoli, eggplant |
| 1 per 9 squares | Zucchini and squash (or one per bed corner, spilling out) |
The densities the calculator applies come from its spacing table per crop, so odd cases (corn at 1 per square in blocks, melons at 1 per 9+) follow from the same numbers rather than a second list to disagree with itself.
Common mistakes
- Square foot densities in unimproved soil. The method’s counts presume its soil recipe: deep, rich, friable. In compacted ordinary soil, thin densities by a quarter or accept the low end of every yield.
- A grid that becomes a cage. The strings and laths are a planning aid, not a religion. Remove them once planting is done if they obstruct hoeing and harvest.
- Forgetting succession in the map. A square foot bed without a succession plan wastes its chief advantage. Every harvested square should have its next crop already chosen.
- Tall crops in the middle. Trellis crops belong on the north edge (northern latitudes) on their squares, or their shade taxes a dozen squares behind them.
Putting the result to work
Draw the grid in the notebook at bed scale, label squares by crop and sowing date, and plan the turnover as squares free up. For beds that mix blocks conventionally instead, the Garden Planner splits by percentage, and the Plant Spacing Calculator handles open ground rows.
How do I plan a square foot bed?
- Enter the bed size in whole feet; the planner counts its squares.
- Pick a crop and the squares it gets.
- Read the plant count at the square foot density and the expected harvest.
- Repeat per crop until the bed’s squares are allocated on your map.
- Record sowing dates per square so succession refills them on time.
How many plants fit in one square foot?
From 16 (carrots, radish) down through 9 (beans, beets), 4 (lettuce, onions), 1 (peppers, kale), to one plant per four or nine squares for tomatoes and squash. The count is set by the plant’s mature footprint, which this planner derives from standard spacings.
Is square foot gardening really more productive?
Per square foot of bed, often yes, because no ground is given to paths inside the bed and densities are high. Per hour of labour it is less clear: the system trades paths for hand work. Its unambiguous win is planning clarity, which this tool borrows: every square has a crop, a count and a date.
What soil does the method assume?
A deep, loose, rich mix (the classic recipe is thirds of compost, peat or coir, and vermiculite) filled to about 6 inches, more for root crops. The densities presume roots can forage freely and water reaches every plant by hand; in ordinary dug soil the same grid works, with yields at the honest low end.
Can I mix crops inside one square?
The classical method says no, one crop per square, which keeps counts and successions legible. Gardeners do mix (radish among carrots as markers and thinners) profitably; when you do, plan that square with the conventional Garden Planner logic instead and keep the map honest.
What happens when a square is harvested?
It gets its next crop the same week: that turnover is the system’s engine. A square of radish (30 days) can turn four times in a season. The planner’s job is to make the counts per turn exact so seed, space and succession all line up.
Densities derived from the standard spacing table used across the Growit tools, consistent with published square foot gardening densities.
