Crop rotation: organising a small vegetable garden

What is crop rotation for?

Avoiding repeatedly planting the same crops in the same location can help slow the build-up of certain pests and diseases associated with those crops. This is the principle outlined by Jardiner Autrement. Complement rotation with monitoring of diseases and soil requirements.

Three- or four-year cycles are organisational models. The RHS offers several approaches depending on the vegetables grown and reserves this method for gardens that are not too small.

Start with a plot history

Draw the cultivated areas and give them stable names: “bed A”, “near the gate”, “north square”. Keep the same reference points from one season to the next, even if you modify the rows.

For each area, record:

• the vegetables grown and, if known, their variety;
• the planting dates and dates when each crop was cleared;
• short-term crops and green manures grown between crops;
• inputs applied and problems observed.

Do not reconstruct from memory a level of precision you do not have: “onions, year uncertain” is usable information. Also distinguish an observation, such as “soft bulbs”, from a confirmed diagnosis.

This is one practical way to keep your garden records. It complements the pre-season plan preparation recommended by the RHS. You can revisit it during the November vegetable garden review.

Look at families, not just the harvested part

Categories such as “leaf vegetables”, “root vegetables”, and “fruiting vegetables” do not correspond to botanical families. Planting a turnip after cabbage changes the harvest but keeps the same family.

This list helps identify crop sequences with little diversity; it does not mean all members of a family have exactly the same diseases. Before planting garlic, check if the plot previously grew onions or leeks.

Create a plan that fits your garden

Proceed in this order:

1. Mark permanently occupied locations. Asparagus and rhubarb remain outside annual rotation, as specified by the RHS.
2. List what you really want to harvest. Do not add a crop just to fill a category in a diagram.
3. Compare possible locations with the history. Look for a different family when growing conditions allow.
4. Check the soil and sun exposure. A damp or shady area may make a move unsuitable: these constraints are noted by Jardiner Autrement.

With two small beds, you may not always be able to replicate a full cycle. Note the compromise made and monitor plant health. A limited rotation remains useful for organising trials, without guaranteeing protection against diseases. When sowing, update the plan with the crops actually planted, including unexpected replacements.

How do you organise a four-year rotation?

If you have four suitable zones, here is an example of organisation proposed by the RHS. It rotates four groups; it does not set sowing dates or fertilisation.

The legumes here include peas, broad beans, and French beans; Brassicaceae include cabbages, turnips, and radishes. The practical group Alliums and other root crops combines garlic, onion, shallot, leek, carrot, and beetroot: it does not form a botanical family. Tomatoes and potatoes belong to the same group in this model. RHS, rotation groups

Record the species actually present, including intercrops. Keep perennials separate. If you lack space for a group, do not plant an unnecessary vegetable just to fill the slot. This diagram does not resolve persistent contamination: read below about the limits for white rot and club root.

Where should you record courgettes, lettuces, and sweetcorn?

The four-group model does not cover all vegetables. The RHS places Cucurbitaceae (courgette, squash, cucumber), salad crops (lettuce, witloof chicory and other chicories), and sweetcorn separately: it positions them where suitable, avoiding frequent replanting in the same spot. This does not reclassify them as root crops or crops without a history.

Add their names to the slot actually occupied and track their succession, even if they serve as an intercrop between two groups in the table. If a disease is identified, its host plants and persistence take priority over this organisational flexibility.

Example with only two zones

Suppose you want tomatoes, French beans, and lettuce. This year, note A: tomatoes and intercropped lettuce; B: French beans, with their actual dates. Next year, first check if tomatoes can move to B and French beans to A: sunlight, drainage, and support must still be suitable. Distribute lettuces where space and season allow, also recording them in the history.

This simple swap is not a four-year rotation: it quickly brings the same crops back to their former locations. If B is too shady or waterlogged for tomatoes, do not force the move; reduce the project, find another suitable location, or record the short interval before growing the crop there again and its limitations. In the presence of a confirmed persistent disease, a two-plot change does not constitute remediation. The site constraints from Jardiner Autrement and the RHS caution about very small gardens remain decisive.

Legumes do not guarantee fertiliser for the following year

Peas, broad beans, and French beans can use atmospheric nitrogen thanks to their association with bacteria. For the following crop, the benefit comes particularly from the plant parts that remain and decompose. Jardiner Autrement describes this gradual release; INRAE also distinguishes harvested seeds from residues left after harvest.

A row of French beans does not mean the plot has all the nitrogen needed for the next crop. Record what was harvested, removed, or left in place, without assuming that this preceding crop alone has saved a particular amount of fertiliser.

Green manures also count in the history. Mustard belongs to Brassicaceae: the RHS advises against following it with other Brassicaceae, particularly due to the risk of club root. A cover crop is not automatically a break for diseases of the relevant family.

When four years of waiting are not enough

Some diseases persist well beyond an ordinary rotation. According to the RHS, the survival structures responsible for onion white rot can remain in the soil for at least fifteen years, although they do not always persist that long. The factsheet considers rotation impractical as a means to resolve established contamination.

For club root in Brassicaceae, the RHS indicates possible contamination for up to twenty years. These durations are not guarantees of subsequently healthy soil.

If a disease is suspected, confirm the diagnosis before deciding on the return of the crop. In the presence of white rot, avoid transferring contaminated soil with tools or footwear to other areas, in accordance with the prevention factsheet. Keep this information in the history: it matters more than completing a rotation cycle.

The steps in pictures

Educational diagram

A plan to keep a record of locations

Example (fictional) · One season: 2026

In the garden

A

Carrots

B

Path

C

RhubarbPermanent location, kept separate

Top view, not to scale.

In the notebook

AZone A · Carrots

Season tracked

2026 fictional

Cultivated species

Carrot

Botanical family

Apiaceae (SNHF)

Fictional observation

“Some gaps in the row.”

AThe same reference links the location to its record.

An example note, without diagnosis or advice for the next crop.