Crop rotation for beginners, with a four-bed plan you can reuse

Crop rotation is simply moving each family of vegetables to a different bed each year, so the same family doesn’t grow in the same soil two years in a row. The classic plan uses four beds and four groups, and each group moves one bed along every spring.

You don’t need to get it perfect. Even a rough rotation does most of the good.

Why bother

Many soil pests and diseases specialise in one plant family. Clubroot attacks cabbages and their relatives, white rot attacks onions and garlic, and potato cyst eelworm builds up under potatoes and tomatoes. Grow the same family in the same place year after year and these problems build up in the soil. Move the family away and they have nothing to feed on.

Different crops also take different things from the soil. Hungry potatoes and squash want lots of compost, peas and beans can add some nitrogen through their roots, and carrots and parsnips prefer soil that wasn’t freshly manured, because fresh manure makes their roots split and fork. A rotation lets you feed each bed for the crop going into it.

The rotation groups

Group	Main crops	Notes
Legumes	Peas, broad beans, runner beans, French beans	Root nodules fix nitrogen from the air. Leave the roots in the ground when you clear them
Brassicas	Cabbage, kale, broccoli, cauliflower, Brussels sprouts, plus radish, turnip, swede, kohlrabi and rocket	Clubroot is the big worry. Like firm soil and plenty of nitrogen
Alliums	Onions, garlic, shallots, leeks	White rot can stay in the soil for many years
Roots	Carrots, parsnips, beetroot, celeriac	Don’t want fresh manure. Often grown with the alliums
Potatoes and tomatoes	Potatoes, tomatoes, peppers, chillies, aubergines	Same family (nightshades), sharing blight and eelworm
Squashes	Courgettes, squash, pumpkins, cucumbers, melons	Fewer soil problems. Fit in where there’s space

The one that catches people out is the brassica group. Radishes, turnips, swedes and rocket look like roots or salads, but they’re cabbage relatives and should follow the brassicas round the plot.

Tomatoes are the other surprise. They’re in the same family as potatoes and catch the same blight, so they belong in the potato group even if they’re grown in a different part of the garden.

A classic 4-bed rotation

Divide the plot into four beds of roughly equal size. Each year, every bed moves on to the next group in the same sequence: potatoes and tomatoes, then legumes, then brassicas, then roots and alliums, then back to potatoes.

	Bed 1	Bed 2	Bed 3	Bed 4
Year 1	Potatoes and tomatoes	Legumes	Brassicas	Roots and alliums
Year 2	Legumes	Brassicas	Roots and alliums	Potatoes and tomatoes
Year 3	Brassicas	Roots and alliums	Potatoes and tomatoes	Legumes
Year 4	Roots and alliums	Potatoes and tomatoes	Legumes	Brassicas

Read any bed down its column and you’ll see the same order, just starting at a different point. Each family comes back to a bed only once every four years.

The order has a reason behind it:

• Potatoes and tomatoes go into the bed that’s had the most compost or manure dug in that winter. They’re hungry crops.
• Legumes follow and need little feeding. Peas and beans add some nitrogen, though much of it leaves with the harvest, so the gain is modest unless you leave the roots in.
• Brassicas come after the legumes to make use of what nitrogen is left. They like firm ground, so don’t dig the bed over deeply before planting.
• Roots and alliums finish the cycle in soil that hasn’t been freshly manured, which is what carrots and parsnips prefer.

Squashes and sweetcorn have no fixed home. Most growers put them with the legumes or in the potato bed. Some use a five-bed rotation that gives the squashes their own bed.

What doesn’t need rotating

• Perennials such as asparagus, rhubarb, globe artichokes, strawberries and perennial herbs stay put for years, so give them a permanent bed outside the rotation. Strawberries are best replaced with new plants on fresh ground every few years.
• Salads like lettuce, spinach and salad leaves are quick and rarely suffer from soil-borne problems. Tuck them into gaps in any bed.
• Annual herbs and flowers such as basil, coriander, marigolds and nasturtiums can go wherever they’re useful.

Rotation in a small space

A strict four-year plan assumes four beds of similar size. Real gardens rarely work out like that. Some honest compromises:

1. Use two or three beds. Combine groups, for example potatoes and tomatoes in one bed, legumes and brassicas in the next, roots and alliums in the third. Two years apart is better than none.
2. Rotate within a bed. In a single raised bed, swap ends each year so the same family isn’t in the same patch.
3. Grow the trouble-makers in containers. Tomatoes and potatoes do well in large pots or bags of fresh compost, which keeps them out of the rotation entirely. Empty the old compost onto the beds afterwards, but not if it carried blight.
4. Keep a record. The hardest part of rotation is remembering what grew where. A sketch of the beds in a notebook each year is enough.

Common mistakes

• Putting turnips and radishes with the carrots. They’re brassicas and can carry clubroot into a bed that was meant to be free of it.
• Bringing the problem back. Rotation won’t help if you dump old brassica stalks or onion skins from a diseased crop onto the next bed. Bin or burn diseased material.
• Expecting rotation to stop blight. Potato and tomato blight spores travel on the wind, so rotation does little against it. Rotation helps with soil pests like eelworm, not airborne disease.
• Giving up after year one. If the beds don’t divide neatly, a rough rotation still beats planting the same thing in the same spot every year.