What is square foot gardening?

A method dividing raised beds into 30 cm (1 ft) squares, each planted with a specific number of plants based on their size. It maximises yield in small spaces.

How many plants per square?

Mel Bartholomew's spacing splits crops by mature size: extra-large (tomato, pepper, cabbage, courgette) = 1 per square (30 cm / 12 in apart); large or leaf lettuce = 4 per square (15 cm / 6 in); medium (bush beans, spinach, beetroot) = 9 per square (10 cm / 4 in); small (radish, carrot, onion) = 16 per square (7.5 cm / 3 in). Peas are an exception at 8 per square.

How deep should a square foot garden bed be?

Minimum 15 cm, ideally 30 cm. Mel Bartholomew (SFG inventor) recommended 15 cm of his special soil mix over existing ground. Deeper beds (25-30 cm) suit carrots, parsnips and other long roots.

What soil mix does square foot gardening use?

Mel's Mix is equal parts by volume: 1/3 blended compost, 1/3 coarse vermiculite, and 1/3 peat moss (or peat-free coir as a sustainable UK substitute). The compost supplies nutrients, while the vermiculite and peat/coir hold moisture yet keep the mix loose and free-draining. No added fertiliser is needed.

GardenCalcs

Square Foot Gardening Calculator — SFG Plant Counts

Plan a square foot garden with correct plant counts per square.

Bed Length

Length of the raised bed (a standard SFG bed is 1.2 m / 4 ft)

Bed Width

Width of the bed — keep it 1.2 m or less so the centre stays within arm's reach

CropPick a crop to set its plants-per-square from Bartholomew's spacing chart

How We Calculate This

The bed is divided into a grid of equal squares (30 cm / 1 ft is standard). Each square is planted according to the crop's spacing needs.

Squares = Floor(Length ÷ Square Size) × Floor(Width ÷ Square Size). Total plants = Squares × Plants per square.

Mel Bartholomew's counts by mature size: 1 (extra-large, e.g. tomato), 4 (large, e.g. lettuce), 9 (medium, e.g. bush beans), 16 (small root veg, e.g. radish).

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates based on standard gardening guidelines. Results may vary with soil conditions, climate, and plant varieties.