Crop rotation

Crop rotation is the simple habit of not growing the same family of vegetables in the same patch of ground two years running. Instead you group your crops by family and move each group on to a fresh bed every year, so that over three or four seasons everything has worked its way around the whole plot before returning to where it started.

Why it works

Most soil-borne pests and diseases are fussy about which plants they attack. Clubroot goes for the cabbage family, onion white rot for the onion family, potato eelworm for spuds. If you grow the same crop in the same spot year after year, those problems build up in the soil until they spoil the harvest. Move the crop on and the trouble is left behind with nothing to feed on, so it fades. Rotation also balances how the soil is used — different families take and give different things — so no one bed gets steadily exhausted.

The four main groups

Beginners usually sort their veg into four families and give each its own bed:

• Potatoes (and the tomato family). Hungry crops that like plenty of compost and a patch of their own, partly to keep blight moving around the plot.
• Legumes — peas and beans. These fix nitrogen from the air and leave the soil richer for whatever follows.
• Brassicas — cabbage, kale, broccoli, sprouts. Greedy for nitrogen and prone to clubroot, so they really benefit from moving around.
• Roots and alliums — carrots, beetroot, parsnips, onions, garlic, leeks. These prefer a soil that wasn't freshly manured, which would make roots fork.

A simple four-bed rotation

Split your growing space into four roughly equal beds and plant one group in each. The following year, shift every group on by one bed and repeat. The usual running order is potatoes, then legumes, then brassicas, then roots and alliums — then back to potatoes in year five.

The clever part is putting brassicas straight after legumes. Peas and beans bank nitrogen in their roots as they grow, and hungry brassicas lap that up the next season, so you get sturdier cabbages and fewer feeds for free. Roots follow the brassicas because they're happy in plainer, leaner soil, and potatoes come round again to ground that has had a year to recover.

Keeping it relaxed

Don't let rotation become a headache. Salad leaves, courgettes and sweetcorn don't belong neatly to any of the four families, so just slot them into whichever bed has room. The aim is only to avoid growing the same family in the same place two years in a row — even a loose, three-bed version is far better than none. For a fuller walk-through with a year-by-year plan, see our guide to crop rotation explained.