WHAT THE GUIDANCE SAYS

Move the beds
along each year.

Grow the same crop in the same soil and its problems build up.

The Royal Horticultural Society's advice for vegetable gardens is simple: group crops by family, split the plot into sections and move each section a step forward every year.

ONE STEP forward each year

Check a crop

An allotment in morning light with neat raised vegetable beds of cabbages, leeks and runner beans climbing bamboo canes, and a path of grass between them — AI-generated image, not a photograph of a real person or place.

Group by family
Move every year
Keep soil off your boots
Easy habits, healthier beds

THE SHORT ANSWER

Group the families,
then rotate them.

Rotation is about pests, diseases and nutrients.
It works best when you plan before you sow.

ROTATE

One step every year

The RHS says rotation helps reduce a build-up of crop-specific pests and diseases, and can help balance soil nutrients and reduce weeds.

See the plan

POTATOES

Starve out the cysts

Potato cyst nematode eggs can survive for up to ten years in some soils, so the RHS suggests at least 5 to 6 years between potato crops where there is a problem.

Check a crop

LEGUMES

Peas and beans first

Plants in the pea and bean family fix nitrogen from the air in their root nodules, though the RHS notes this happens only in summer.

Green manures

A QUICK CROP CHECK

How much does
rotation matter?

Pick a crop group to see what the RHS says about where it goes. The bar shows how strongly the guidance points to keeping it on the move.

Crop check

Choose a crop groupSalads, squash and sweetcornPeas and beansCabbages and other brassicasPotatoes and tomatoesOnions, garlic and leeks

Salads, squash and sweetcornAnywhere

Cucurbits, salads and sweetcorn can go wherever is convenient. The RHS only advises avoiding growing them too often in the same place.

Peas and beansMove yearly

Legumes take their turn in the rotation. They store nitrogen from the air in root nodules, but only in summer.

Cabbages and other brassicasRotate and lime

Club root spores can contaminate soil for up to 20 years. Raising soil pH reduces club root but does not eliminate it, and gardeners have no chemical treatment.

Potatoes and tomatoes5–6 years if cysts

Potato cyst nematodes build up quickly if potatoes or tomatoes are grown often in the same soil. Where they are a problem, the RHS suggests rotating for at least 5 to 6 years.

Onions, garlic and leeksKeep it out

White rot can stay in soil for at least 15 years, which makes rotation impractical once it is established. The main defence is not bringing it in on tools or boots.

Sources: RHS advice pages on crop rotation, club root, onion white rot, potato cyst nematodes and green manures.

Based on Royal Horticultural Society advice on crop rotation, club root, onion white rot and potato cyst nematodes. General gardening information only.

TWO NUMBERS WORTH KNOWING

Some problems
outlast any plan.

Rotation slows soil problems down.
A few last longer than any rotation can.

20 years

How long resting spores can stay in soil

The RHS says club root resting spores can contaminate soil for up to 20 years. It affects cabbages, sprouts, cauliflowers, turnips, swedes and radishes, and relatives such as wallflowers.

CLUB ROOT · RHS

15+ years

How long sclerotia can stay in soil

Onion white rot sclerotia can remain in the soil for at least 15 years, the RHS says, though they will not always survive that long.

WHITE ROT · RHS

For both diseases the RHS stresses hygiene: buy brassica plants from a club root-free source and avoid moving contaminated soil on tools, wheelbarrows or footwear, especially on shared plots such as allotments.

THE THREE-BED PLAN

Three sections,
three years.

This is the RHS's three-year plan, built around potatoes and brassicas. Each year, move every section one step forward.

Split the plot into three
Make three equal sections, plus an extra one for perennials such as rhubarb and asparagus if you grow them.
Year one
Section 1 potatoes; section 2 legumes, onions and roots; section 3 brassicas.
Year two
Section 1 legumes, onions and roots; section 2 brassicas; section 3 potatoes.
Year three
Section 1 brassicas; section 2 potatoes; section 3 legumes, onions and roots. Then start again.

Broad bean plants in flower in a vegetable bed, with black and white blossoms and young green pods — AI-generated image, not a photograph of a real person or place.

Gloved hands lifting freshly dug potatoes from dark soil with a garden fork, the tubers resting on the surface — AI-generated image, not a photograph of a real person or place.

FOUR BEDS AND GREEN MANURES

More beans,
fewer potatoes.

If you grow more legumes and onion-type crops and fewer potatoes and brassicas, the RHS suggests a four-year plan, with legumes, brassicas, potatoes, and onions and roots each moving one bed along every year.

Green manures need a place in the rotation too, because they can suffer the same diseases as vegetables in their family. The RHS warns that mustard, a brassica, should not be followed by other brassicas, as it could encourage club root.

Questions

Questions people ask

Why rotate vegetable crops at all?

The RHS says crop rotation helps reduce a build-up of crop-specific pests and diseases. Changing crops each year can also help balance soil nutrients and reduce weed problems.

What are the main rotation groups?

The RHS uses brassicas, legumes, onions, the potato family and roots. Peppers and aubergines can go anywhere in the rotation, and cucurbits, salads and sweetcorn wherever is convenient.

Is a three- or four-year rotation better?

Both appear in RHS guidance. The three-year plan suits plots built around potatoes and brassicas; the four-year plan suits growers who want more legumes and onion-type crops and fewer potatoes and brassicas.

Does rotation cure club root?

No. The RHS says club root spores can stay in soil for up to 20 years. Raising soil pH reduces it but does not eliminate it, and there are no chemicals available to gardeners to treat it.

Where do rhubarb and asparagus go?

Perennials stay put. The RHS suggests dividing the plot into equal sections for the rotation, plus an extra section for perennial crops.

Move the beds
along each year.