Guides
What Is Square Foot Gardening?
The simplest way to grow a lot of vegetables in a small raised bed - a grid, a spacing rule, and good soil. Here is exactly how it works.
Square foot gardening (SFG) is a method for growing vegetables in a small raised bed divided into a grid of 1-foot squares. Instead of planting in long rows with wide gaps between them, you plant a set number of vegetables in each square. Retired engineer Mel Bartholomew created the system and published it in his 1981 book Square Foot Gardening. It caught on because it makes the two things beginners get wrong - spacing and soil - almost impossible to mess up.
The three ideas that make it work
SFG is really just three rules working together. Get these and you understand the whole method.
- A small bed, usually 4 feet by 4 feet. Four feet is the magic number because you can reach the middle from any side without stepping on the soil. Compacted soil is a beginner garden killer, and this layout removes the temptation entirely. According toWashington State University Extension, the standard bed is 4 feet by 4 feet with 6 inches of soil, divided into sixteen 1-foot squares.
- A physical grid on top. You lay a real grid - lath strips, string, or thin wood - across the bed so the sixteen squares are visible. This is not decoration. The grid is what keeps you planting at the right density instead of scattering seed.
- Good soil you add, not the dirt already there. SFG beds are filled with a light, fluffy blended mix (Mel's Mix) rather than native ground soil, so you skip the years of soil improvement a traditional plot needs. More on that in theraised bed soil mix guide.
The spacing rule: 1, 4, 9, or 16 per square
This is the part people remember. Each square holds a fixed number of one crop, based on how much room that plant needs. TheSquare Foot Gardening Foundationsorts plants into four sizes:
| Plant size | Per square | Spacing | Examples |
|---|---|---|---|
| Extra-large | 1 | 12 in | Tomato, pepper, broccoli, cabbage, eggplant |
| Large | 4 | 6 in | Leaf lettuce, chard, potatoes, corn |
| Medium | 9 | 4 in | Bush beans, spinach, beets, turnips |
| Small | 16 | 3 in | Carrots, radishes, onions, chives |
The trick for any plant not on the list: read the seed packet. Find the line that saysthin to X inches apart and match X to the table. Thin to 3 inches means 16 per square, thin to 4 inches means 9, thin to 6 inches means 4, and thin to 12 inches means 1. That single habit replaces every spacing chart you will ever need. Ourplant spacing chart already has the common crops worked out.
Why it beats traditional rows for small gardens
A traditional row garden spends huge amounts of ground on walking paths - often more path than plants. A 4x4 SFG bed uses almost the entire surface for growing. Because everything is packed at its correct final spacing, the leaves knit together into a canopy that shades the soil, which means far fewer weeds and less water lost to evaporation. You also plant less: you sow two or three carrot seeds per hole instead of a whole row you later rip out. Bartholomew's original pitch was that SFG gives the same harvest as a row garden in about 20 percent of the space with a fraction of the work, and for a small backyard bed that holds up well.
How to start one this weekend
- Build or buy a 4x4 frame. Untreated lumber, 6 inches tall, set on level ground in a spot that gets 6 to 8 hours of sun.
- Fill it with about 8 cubic feet of Mel's Mix - roughly a third compost, a third peat moss or coconut coir, a third coarse vermiculite.
- Add the grid so you can see all 16 squares.
- Plant by the numbers. Pick a crop per square and use the 1/4/9/16 rule. For a finished plan you can copy, see what to plant in a 4x4 garden.
- Water gently and often at first, then let the canopy do the rest.
That is the entire method. A grid, a spacing rule, and good soil. Everything else - companion planting, succession sowing, vertical trellises - is optional refinement on top of these bones.
Frequently asked questions
How big is a square foot garden?
The classic size is a 4 feet by 4 feet raised bed, 6 inches deep, divided by a physical grid into sixteen 1-foot squares. Four feet is the key number: you can reach the center from any side without stepping on the soil. If a bed sits against a wall, make it 4 feet by 2 feet instead so you never have to reach more than 2 feet.
How many plants can I grow per square?
One, four, nine, or sixteen, depending on the plant's size. One extra-large plant per square (tomato, pepper, broccoli), four large plants (lettuce, chard), nine medium plants (bush beans, spinach, beets), or sixteen small plants (carrots, radishes, onions). It maps to 12-inch, 6-inch, 4-inch, and 3-inch spacing.
Is square foot gardening better than rows?
For a small home garden, usually yes. A grid uses almost all the bed area for plants instead of leaving wide walking rows, so a 4x4 bed produces far more than 16 square feet of a traditional row garden. Rows still win for large plots you work with a tiller or tractor.
How deep does the bed need to be?
Six inches of good soil grows most vegetables, including carrots and beets. Only a few crops want more: for full-size root crops or potatoes, add a couple of inches or build the bed 10 to 12 inches deep.
Plan your bed square by square
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