Eleanor Whitaker
Why rotation earns its keep
In a small kitchen garden, every bed is precious. You cannot afford to let one go sick. Yet the biggest mistake I see on smallholdings and allotments is growing the same crops in the same spot year after year. It feels tidy and familiar, but it quietly builds trouble. Pests and diseases that overwinter in the soil — clubroot in brassicas, carrot fly larvae, potato eelworm — multiply where their favourite plants reappear. Nutrients also drift out of balance: heavy feeders strip nitrogen, while others leave the soil tired and compacted. Rotating your crops between beds is the simplest, cheapest and most effective way to break those cycles. No chemicals, no expensive inputs, just a pencil and a plan.
The four groups to know
Before you move anything, sort your crops into families. For a kitchen garden, four groups cover almost everything.
- Legumes — peas, broad beans, runner beans, French beans. Their roots carry nodules that fix nitrogen from the air, so they leave the soil richer than they found it. Do not manure the bed before planting them; they will grow soft and leafy instead of podding well.
- Brassicas — cabbage, kale, Brussels sprouts, broccoli, cauliflower, plus swede, turnip and radish. These are hungry, lime-loving plants that need firm soil. They suffer most from clubroot, so never follow one brassica with another.
- Roots — carrots, parsnips, beetroot, and the alliums: onions, garlic, leeks and shallots. They dislike fresh manure, which makes carrots fork and onions bolt. They do best in soil left reasonably firm and low in nitrogen.
- Potatoes and others — potatoes, plus salad leaves, courgettes, sweetcorn and squash. Potatoes are useful soil breakers, but they need plenty of organic matter and leave the ground lumpy.
Keep swede and turnip with the brassicas, not the roots, even though they look like root crops. That is a common slip.
A simple four-bed plan
Divide your plot into four beds — call them A, B, C and D. In year one, grow legumes in A, brassicas in B, roots in C, and potatoes in D. The following spring, move everything one bed clockwise: potatoes into A, legumes into B, brassicas into C, roots into D. Year three shifts again, and year four completes the circle. By year five you are back where you started, but the soil is healthier and the pests are confused.
If you garden on a smaller scale, three beds work too. Combine potatoes with the roots group, or grow potatoes in bags and keep three clean beds for legumes, brassicas and roots. The principle is what matters: never follow a crop with another from the same family.
Feeding and liming as you rotate
Rotation and soil care go hand in hand. Apply well-rotted manure or compost to the potato bed in autumn, and let the worms work it in. The legume bed needs nothing more than a little compost; too much nitrogen and you will get leaves, not pods. The brassica bed benefits from lime, scattered in autumn and left for the winter to sweeten the soil. Aim for a pH around 6.5 to 7.0 for brassicas. Never lime immediately before potatoes, though — it encourages scab. The root bed should get only the leftovers: a light dressing of compost from the previous year's heap, nothing fresh.
Green manures and empty beds
Sometimes a bed sits empty for a few months, especially after early potatoes or before winter. Sow a green manure instead of leaving bare soil. Field beans and grazing rye are hardy and will hold nutrients through the winter. Phacelia is quick and pretty, and its roots break up heavy ground. Mustard is useful but avoid it if clubroot is present, as it can host the disease. Cut green manures down before they flower and set seed, then leave the tops on the surface as a mulch. The roots die back and feed the soil life beneath.
Keeping records and staying flexible
None of this works without a notebook. Write down what grows where, when you sowed, what pests appeared and what the harvest was like. A simple grid in a shed diary is enough. Labels help too, especially for overwintering crops. On a small plot you will sometimes break the rules: a self-seeded parsley, a stubborn rhubarb crown, a bed of strawberries that stays put for three years. That is fine. Permanent crops like rhubarb, asparagus and fruit bushes sit outside the rotation. The aim is not a perfect system but a living one. Move what you can, feed the soil, and let the beds rest when they need to. Your carrots will thank you, your cabbages will heart up, and you will use less weedkiller and bug spray than you ever thought possible.
