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Raised bed crop rotation is an annual planning method: divide the growing area into sections, assign each section to a crop group, and move every group one step forward each year. For a small plot, a three-year rotation based on the RHS groups is usually the most workable plan.
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Why rotate in a raised bed
Soil-borne pests and diseases tend to attack specific plant families repeatedly. Moving crops to a different section each year gives those pests and pathogens a season without their host, which can reduce the build-up of damaging populations. Rotation also helps even out nutrient removal, because different crop groups take up different balances of nitrogen, phosphorus and potassium. Some crops, such as potatoes and squashes, have dense foliage that suppresses weeds, reducing maintenance in following crops.
Raised beds have a finite volume of soil, so rotation is useful but not a substitute for annual feeding. Check organic matter and feeding needs for the crops and existing soil; rotation does not remove those needs, but every bed does not automatically require manure or extra fertiliser each year. The bed system itself helps: because you work from the edges, you avoid treading on the soil, and compost can be concentrated on the growing area rather than wasted on paths.
Crop groups for a small plot
Group your annual vegetables into these planning groups (not all are single botanical families), following the RHS advice:
- Brassicas: Brussels sprouts, cabbage, cauliflower, kale, kohlrabi, oriental greens, radish, swede, turnips
- Legumes: peas, broad beans, French beans, runner beans
- Onions: onion, garlic, shallot, leek
- Potato family: potato, tomato; peppers and aubergines are also in this family and should be included when planning around a diagnosed shared disease
- Roots: beetroot, carrot, celeriac, celery, Florence fennel, parsley, parsnip and other root crops except swedes and turnips, which are brassicas
Some annual crops do not need a fixed place: courgettes, pumpkins, squashes, marrows, cucumbers, salads such as endive, lettuce and chicory, and sweetcorn can be grown wherever convenient, as long as you avoid growing them too often in the same spot. Perennial vegetables such as rhubarb and asparagus stay outside the rotation.
A three-year planning example
Dividing one small bed into sections does not isolate soil-borne disease. Roots and soil movement cross the boundaries. Use the layout to organise planting, with modest expectations for disease control compared with rotating across larger separated beds.
If you have a single raised bed, divide it into three sections of roughly equal size. If you have several small beds, treat each bed as one section. The RHS three-year rotation works well when potatoes and brassicas are important crops:
| Year | Section A | Section B | Section C |
|---|---|---|---|
| Year 1 | Potatoes | Legumes, onions and roots | Brassicas |
| Year 2 | Legumes, onions and roots | Brassicas | Potatoes |
| Year 3 | Brassicas | Potatoes | Legumes, onions and roots |
Each year, every group moves one section forward. Brassicas follow legumes, onions and roots; legumes, onions and roots follow potatoes; potatoes follow brassicas.
If you grow few potatoes and brassicas but many legumes and onion-type crops, the RHS four-year rotation separates legumes, brassicas, potatoes, and onions and roots into four sections. The principle is identical: each group moves one step forward every year. For most small raised beds, the three-year plan is easier to manage because it needs only three sections.
Worked example: dividing a small bed
Assume you have a raised bed 2.4 m long and 1.2 m wide. To create three equal sections, divide the length by three: 2.4 m ÷ 3 = 0.8 m. Each section is therefore 0.8 m by 1.2 m. This calculation assumes the bed is rectangular and that you want equal areas for each group. In practice, adjust section sizes to match how much of each crop you actually want to grow. If one section is too small for a worthwhile potato crop, grow potatoes in containers outside the bed and use that section for another group. If your bed is not rectangular, or if you want unequal sections, mark out the areas with string and adjust until the proportions match your intended harvest. The key is to keep the same sections from year to year so the rotation stays consistent.
Spacing crops in raised beds
Beds worked from the edges can sometimes use closer row spacing because access paths between rows are unnecessary. The RHS suggests a general rule of thumb of a 20 per cent reduction in spacing. For example, if a seed packet recommends 30 cm between rows, in a raised bed you might use 30 cm × 0.8 = 24 cm. This is a starting point, not a universal rule: always check the seed packet for the specific variety, and adjust for the vigour of the crop and the depth of your bed. Overcrowding can increase disease and reduce yields. Remember that the 20 per cent reduction assumes you can reach all parts of the bed from the edge. If the bed is wider than your comfortable reach, improve access or narrow the growing area rather than relying on an unsupported plank across its sides.
Timing and succession within the rotation
The RHS vegetable crop planner groups crops by time from sowing or planting to harvest: speedy crops are ready in 3–13 weeks, medium-term crops in 14–25 weeks, and slow or long-season crops in 26–52 weeks. Use these timings to plan succession within each section. For example, first early potatoes can be lifted by midsummer, leaving space for a quick crop such as lettuce, radish or spinach before the section moves to its next rotation group the following year. Record the family of the follow-on crop as part of the rotation too: radish is a brassica, for example. When choosing succession crops, check the days to maturity on the seed packet and count back from the expected first frost in your area. This is especially important for late sowings of quick crops.
Keeping the plan on track
Mark out the sections on the ground before the growing season starts, using string, pegs or temporary boards. Keep a simple record of what was planted in each section each year, either in a notebook or on weatherproof labels. Flexible crops such as courgettes and salads can be slotted into gaps, but note where they were grown so you can avoid repeating the same spot too often. If you have two small beds, you can still run a three-year rotation by dividing one bed into two sections, giving three sections in total. Alternatively, grow a group in suitable containers with an appropriate medium. Moving the same pot and soil to a different position does not itself interrupt soil-borne disease.
Limits and decisive checks
Rotation reduces the build-up of crop-specific problems but does not eliminate them. Some soil-borne diseases, such as clubroot in brassicas and onion white rot, can persist for many years, so rotation alone may not be enough in badly affected soil. Very small beds may not support a full three-year rotation; in that case, record crop families and avoid unnecessary repetition, without treating a two-year gap as effective control for every disease, and consider growing potatoes or brassicas in containers. Always check seed packet spacing and variety-specific needs before planting, and assess soil improvement and feeding separately from the rotation. Finally, rotation is a planning tool, not a guarantee. Observe your plants each season and adjust the plan if a particular pest or disease appears repeatedly; you may need to lengthen the gap for that crop family or stop growing susceptible crops in affected soil for the period recommended for the diagnosed disease.
Useful products for this job
The links below open Amazon UK product searches. Check the exact item, seller, current price and compatibility before buying.
- Raised bed divider boards or edging: Optional visible markers for rotation sections; they do not isolate soil-borne pests or disease. A drawn plan or labels can do the same planning job. Check fit, safe edges and soil-contact suitability; do not buy dividers expecting them to create disease-proof compartments. Search Amazon for Raised bed divider boards or edging.
- Weatherproof plant labels: Useful for recording which crop group was in each section each year, so you can follow the rotation without relying on memory. Look for UV-stable labels that will not become brittle outdoors; check they are large enough to write the crop name and year clearly with a pencil or permanent marker. Search Amazon for Weatherproof plant labels.
Related garden guides
- Green manures for vegetable beds: choosing and clearing a crop
- No-dig vegetable beds: starting with mulch and managing weeds
- More planters & pots guides
Sources and further guidance
Guidance researched in September 2026. The feature image is an AI-generated illustration. Product guidance is based on published information, not hands-on testing.