Crop rotation on an allotment
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Crop rotation means growing related crops together and moving each group to a different bed every year. It helps stop soil-borne pests and diseases building up, and it lets crops that need different soil conditions follow each other.
The four groups
| Group | Crops |
|---|---|
| A: Peas, beans and onions | Broad beans, peas, runner and French beans; onions, shallots, garlic, leeks |
| B: Cabbage family | Cabbage, kale, Brussels sprouts, broccoli, cauliflower, swede, turnips, radishes |
| C: Roots | Carrots, parsnips, beetroot |
| D: Potatoes and tomatoes | Potatoes and outdoor tomatoes (same family, and they share blight) |
Some crops fit anywhere: courgettes, squash, sweetcorn, lettuce, spinach and chard can fill gaps. Perennials such as rhubarb, asparagus and soft fruit live in a permanent bed.
How the beds move
With four beds, each group moves one step every year: A → B → C → D → back to A.
| Bed | Year 1 | Year 2 | Year 3 | Year 4 |
|---|---|---|---|---|
| 1 | A | B | C | D |
| 2 | B | C | D | A |
| 3 | C | D | A | B |
| 4 | D | A | B | C |
Brassicas follow peas and beans in this order, which is a common pattern. Swedes, turnips and radishes are brassicas, so they go with the cabbage family, not the roots.
What rotation won't do
Rotation helps, but it isn't a cure. Clubroot, for example, can stay in soil for many years, so moving brassicas round a small plot won't clear it. If you've got a persistent soil problem, read the RHS advice on that disease.
FAQs
Is a 3-year rotation enough?
Many growers use three groups (for example, putting potatoes with roots). Four groups gives each family longer away from a bed. Use what fits your number of beds.
What if I don't have four beds?
Divide one bed into sections, or use the planner below with your plot size. It tells you when groups have to share.
Allotment plot planner
Worked example
For a half plot (5 poles, about 126 m²), a quarter already clear, 4 hours a week, a shed and compost bays:
- 10 beds of 1.2 m with 45 cm paths, beds running across a plot about 19.5 m by 6.5 m
- Rotation: 8 beds in four groups, moving one step each year
- Broad beans: room for about 64 plants; Onions (sets): room for about 256 plants; Cabbage: room for about 56 plants; Carrots: room for about 1480 plants; Potatoes: room for about 86 plants; Courgettes: room for about 14 plants
- Clearing: about 95 m² to clear, roughly 12 weeks at 4 hours a week (our rule of thumb of 2 m² an hour)
- A 5 cm compost mulch over all the beds: about 3.9 m³, or 78 bags of 50 litres
Based on: National Allotment Society (NSALG), RHS. Crop spacing from RHS grow-your-own guides.
Sources
- National Allotment Society (NSALG): A traditional full allotment plot is 10 poles (rods or perches), about 250 square metres awaiting check
- RHS: RHS crop rotation: group crops (legumes and onions, brassicas, potatoes, roots) and move each group to a new bed every year to limit soil pests and diseases checked 24 Oct 2026
- RHS: RHS: clubroot persists in soil for many years; lime and drainage help, rotation alone won't clear it awaiting check