Square-foot spacing in a nutshell
Instead of rows, intensive small-space gardening divides a bed into 30 cm squares and plants each square at a fixed density: one large plant (tomato, pepper, kale), four medium plants (lettuce, chard, basil), nine small plants (spinach, beets, bush beans) or sixteen tiny ones (radish, carrots, spring onions). Dense planting shades out weeds and makes the most of expensive container soil.
Use at least 15 cm of soil depth for greens and herbs, 20–30 cm for roots and fruiting crops. Put tall and climbing plants on the side that won’t shade the rest — usually the north side in the Northern Hemisphere.