Square Foot Gardening Plant Capacity
Pick one of four crops and how many 30 cm squares you have to get the plant total: tomato 1 per square, lettuce 4, beet 9 and carrot 16.
Plantas totais
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Square Foot Gardening: Mel Bartholomew's method
Engineer Mel Bartholomew came up with Square Foot Gardening (SFG) in 1981. The idea is to split a raised bed into 30 × 30 cm (1 ft × 1 ft) blocks, then plant each block with a set number of plants based on how big they get at maturity. The densities he settled on are 1 plant per square foot for large crops (broccoli, cabbage, tomato, pepper), 4 per sq ft for medium ones (lettuce, swiss chard, parsley), 9 per sq ft for small (bush beans, beets, spinach), and 16 per sq ft for the tiny stuff (carrots, radishes, chives, onions). To put that into numbers: a 4 × 4 ft bed gives you 16 blocks, and in just 4 of them you could fit 1 broccoli, 4 lettuces, 9 carrots and 16 chives. The bed is filled with Mel's Mix (1/3 compost, 1/3 peat, 1/3 vermiculite) at only 15 cm depth, which cuts water use by roughly 80% compared with traditional rows.
Applications
Urban gardens in apartments, balcony vegetable beds, school and therapy plots, hydroponics or aquaponics planning (the same density logic carries over to NFT/DWC channels), and basically any growing where space is tight. That includes wheelchair-accessible setups, rooftops and raised beds built for older gardeners.
FAQ
Why exactly 1 square foot? Mel noticed that 30 cm lines up with how wide most vegetables spread once they're grown, so you get sensible spacing without doing the math off the back of a seed packet.
What about climbers like tomato and cucumber? Plant one per square foot and train it up a vertical trellis on the north side of the bed, where it won't cast shade over the other blocks.
Can I rotate crops within blocks? Yes. Once you harvest, top the block up with fresh compost and replant with a different plant family so the soil doesn't wear out.
Minimum bed size? Even a single 1 ft × 1 ft block will give you a harvest, though most people start with 2 × 2 ft (4 blocks). Keep the width under 4 ft so you can reach the middle without having to step into the bed.
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