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Square Foot Gardening

Square Foot Gardening (SFG) is a vegetable-growing method that divides a raised bed into a grid of 1-foot (30 cm) squares. Each square is planted with 1, 4, 9 or 16 plants — the exact number depending on how much space that crop needs. Compared with traditional row gardening, SFG produces comparable yields on roughly 20 % of the area, uses far less water, and almost eliminates weeding.

Where SFG comes from

  • SFG was developed by American engineer Mel Bartholomew in the late 1970s. Frustrated by the wasted space, water and effort of conventional row gardens, he sketched a bed where every square foot was deliberately planned. His book "Square Foot Gardening" (1981) and the PBS TV show that followed turned it into one of the most-copied small-space gardening methods of the last 40 years.
  • A revised version ("All New Square Foot Gardening", 2006) introduced the raised-bed-on-soil variant and the now-famous "Mel's Mix" soil recipe. The core idea has stayed the same: maximum harvest from minimum space with minimum effort.

    • Why SFG beats row gardening

    A typical 1.2×1.2 m SFG bed produces roughly the same harvest as a 4×8 m traditional row garden. The comparison below explains why.

    Square Foot Gardening

  • 80 % less space — every square is usable growing area, no wasted paths between rows.
  • 90 % less water — targeted watering into squares, no spray onto bare soil between rows.
  • Almost no weeding — intensive planting shades out weed seedlings before they establish.
  • Clear plan — the grid tells you exactly what goes where and how much of each crop.
  • Accessible — raised beds at 25–40 cm height mean no bending or kneeling; reachable from all sides without stepping in.

    • Traditional row garden

  • Large area needed with wide paths between rows; most of the garden is walkway, not growing space.
  • Sprinklers or hoses water the paths too, wasting 60–70 % of the water.
  • Bare soil between rows germinates weeds for weeks; weekly weeding is the norm.
  • Typical advice is "thin out to 15 cm spacing" — you sow 10× the seeds you actually need.
  • Requires digging and turning every spring; compacted soil over time.

    • The 10 core rules

    Mel's "10 commandments" — the steps that separate a true SFG bed from a random raised bed.

  • Build a raised bed, typically 1.2×1.2 m (4×4 ft) or 1.2×2.4 m (4×8 ft), at least 15 cm deep — 20–30 cm is ideal.
  • Divide the bed into 30×30 cm (1×1 ft) squares with a visible grid — wooden slats, string or rope work equally well.
  • Fill with "Mel's Mix": one-third compost, one-third coir (or bark/compost alternatives — not peat, see below), one-third vermiculite.
  • Plant 1, 4, 9 or 16 plants per square depending on mature plant size — the classic SFG grid formula.
  • Reach the bed from all sides — never step inside. The narrow width (max 1.2 m) is deliberate.
  • Build a vertical support (trellis, netting, cage) for climbing crops — a single square can grow a whole cucumber harvest going up.
  • Water by hand at the base of each plant, not on the leaves, not with a sprinkler. One square at a time.
  • Plan crop rotation and companion planting inside the grid — use PlotMate's optimizer to help.
  • As soon as a square is harvested, top it up with a trowel of compost and replant with the next crop (succession planting).
  • Cover your soil — mulch the squares in summer to conserve moisture; cover empty squares in winter with compost or a green manure.

    • Mel's Mix

    The soil recipe that makes SFG work: light, fluffy, holds water like a sponge, drains well, and is rich in nutrients. Even a complete gardening beginner gets good results in year one because the mix itself is near-perfect.

    Compost

    Coir (coconut fibre)

    Vermiculite

    Compost (1/3)

    Use at least 5 different compost sources if you can (home compost, bagged garden compost, leaf mould, worm compost, well-rotted manure). The variety gives a broader spectrum of nutrients and microbes. Never use compost alone — it compacts and waterlogs without the other two parts.

    Coir (1/3)

    Coconut-fibre coir (Kokosfaser) sold as compressed bricks. Soak in water and it expands 5–7×. Holds water, stays light, and is a renewable by-product of the coconut industry. This is where Mel's original recipe used peat moss — read the warning below.

    Vermiculite (1/3)

    Puffed mica — small, shiny, lightweight flakes that hold water and air pockets. Use coarse horticultural grade (perlite is an acceptable substitute if vermiculite is hard to find). Never use construction-grade vermiculite — different purity.

    Why skip peat moss: Mel's original 1981 recipe called for peat. We now know peatlands are one of the planet's biggest carbon sinks, second only to oceans — harvesting peat releases millennia of stored CO₂ and destroys unique bog ecosystems. Coconut coir, composted bark or leaf mould are climate-friendly alternatives with virtually identical results. In many countries (UK, Germany, Ireland) peat is already being phased out of amateur gardening. Please choose coir.

    Plants per Square Foot

    The density is based on the mature size of the plant, not its current seedling size. A carrot only needs 8 cm of space, so 16 fit in a 30×30 cm square. A tomato needs 30 cm to itself.

  • Large (tomato, pepper, cabbage)
  • Medium (lettuce, basil, chard)
  • Small (beans, peas, beetroot)
  • Tiny (carrots, radishes, onions)

    • Density examples in detail

    How to read the grid: imagine each square divided into a 2×2, 3×3 or 4×4 mini-grid. The density number is how many plants you place at those mini-grid crossings.

    1 per square (very large)

    Tomato, pepper, aubergine, broccoli, cauliflower, kohlrabi (larger varieties), zucchini, corn. These plants would crowd each other above ground. Place one plant in the centre of the square.

    4 per square (medium)

    Lettuce, chard, basil, parsley, kohlrabi (small varieties), leeks, strawberries, bush beans. Arrange in a 2×2 pattern with 15 cm between plants.

    9 per square (small)

    Peas, beets, spinach, turnips, small bush beans, bunching onions. Arrange in a 3×3 pattern with 10 cm spacing.

    16 per square (tiny)

    Carrots, radishes, onions (from sets), garlic, spring onions. Arrange in a 4×4 pattern with 7.5 cm spacing. A single square easily yields a kilogram of carrots.

    Common beginner mistakes

  • Skipping the grid — "I'll imagine the squares." You won't. Without a visible grid, SFG just becomes a dense raised bed.
  • Using only topsoil or garden compost to fill the bed. The mix must be light and fluffy — plain garden soil compacts and drowns roots.
  • Over-watering the fluffy new mix. It holds water like a sponge — check with your finger before reaching for the hose.
  • Planting by "what looks right" rather than the density chart. Planting 4 tomatoes in one square is the classic first-year disaster.
  • Building too wide a bed (over 1.2 m). You'll end up stepping into it, compacting the mix and snapping plants.

    • Don't wait for the perfect setup. A 1.2×1.2 m bed with any decent mix is better than a "perfect" bed you never build. Start small this season, learn by doing, and expand next year once you know what you love to eat and what actually thrives in your spot.