How to Use This Calculator
- Enter your raised bed dimensions in feet (standard is 4 x 8).
- Select a vegetable from the dropdown — spacing is pre-filled based on square foot gardening guidelines.
- See your layout: total plants, number of rows, and plants per row.
- Use “Custom spacing” if your plant is not in the list.
Square Foot Gardening Spacing Chart
Square foot gardening divides beds into 1 ft x 1 ft squares. Each square gets a specific number of plants based on their spacing needs. This method maximizes yield and minimizes wasted space.
| Vegetable | Spacing | Per Square Foot | In a 4x8 Bed |
|---|---|---|---|
| Radishes | 2 inches | 16 | 512 |
| Carrots | 3 inches | 16 | 512 |
| Onions | 4 inches | 9 | 288 |
| Lettuce | 6 inches | 4 | 128 |
| Bush Beans | 6 inches | 4 | 128 |
| Herbs (basil) | 6 inches | 4 | 128 |
| Peppers | 12 inches | 1 | 32 |
| Cucumbers | 12 inches | 2 | 64 |
| Tomatoes | 24 inches | 1 | 8 |
| Squash | 24 inches | 1 | 8 |
Why Square Foot Gardening Works
Traditional row gardening wastes 50-80% of space on paths between rows. Square foot gardening eliminates row spacing entirely. Plants grow in a grid pattern with just enough room for each one. The result: 5x more produce per square foot compared to traditional rows.
The method also reduces weeding (dense planting shades out weeds), uses less water (smaller area to irrigate), and makes crop rotation easy (just reassign squares each season).
Companion Planting Tips
- Tomatoes + basil — basil repels aphids and may improve tomato flavor.
- Carrots + onions — onion scent repels carrot fly; carrot scent repels onion fly.
- Lettuce + radishes — radishes break up soil for lettuce roots and mature before lettuce needs the space.
- Avoid: tomatoes + peppers in the same square. Both are heavy feeders and compete for nutrients.
FAQ
What size raised bed is best for square foot gardening?
The classic size is 4 x 4 feet — you can reach the center from any side without stepping in the bed. For more planting area, go 4 x 8 feet but make sure you can access it from both sides.
Can I mix vegetables in the same bed?
Absolutely. That is the whole point of square foot gardening. Plant different vegetables in different squares. Just group plants with similar water needs together and put taller plants on the north side so they do not shade shorter ones.
How deep does a raised bed need to be for vegetables?
Most vegetables do fine in 6-8 inches of soil. Root vegetables like carrots and parsnips need 10-12 inches. Tomatoes and peppers prefer at least 12 inches for strong root development.