How to Set Up a Four-Year Crop Rotation Plan

A four-year crop rotation is the gold standard for kitchen garden management. By dividing your growing space into four sections and moving the major crop groups forward one position every year, you ensure that no plant family returns to the same ground for four seasons. This is long enough to break the life cycles of most serious soil-borne diseases and to prevent nutrient depletion in any single bed.

The Four Groups and Their Order

The classic four-year plan uses these groups in this order: potatoes (including tomatoes and peppers), then brassicas (cabbage, kale, broccoli, Brussels sprouts), then legumes and roots combined or separately (peas, beans, carrots, parsnips, beetroot), and finally alliums and miscellaneous (onions, garlic, leeks, plus cucumbers and courgettes). Some growers split roots and legumes into separate groups, using five beds, but four is the most practical arrangement for a standard plot.

The key rule is that potatoes always precede brassicas. Potatoes loosen the soil deeply as tubers swell, and the earthing-up process leaves the bed friable and well-aerated — exactly what brassica roots prefer. Brassicas are heavy nitrogen feeders, so they follow potatoes which have already depleted much of the previous season's compost. Legumes follow brassicas and restore nitrogen through root nodule fixation. Alliums come last, benefiting from the residual fertility left by legumes, and then the cycle restarts with potatoes.

Laying Out the Four Beds

Your four sections do not need to be equal in size, but they should be in fixed positions that you can identify clearly each year. Label them Bed A, B, C, and D — or use pegs, paint, or a sketch on paper. At the start of Year 1, Bed A gets potatoes, Bed B gets brassicas, Bed C gets legumes and roots, and Bed D gets alliums. In Year 2, everything moves clockwise (or in your chosen direction): Bed A now has alliums, Bed B has potatoes, Bed C has brassicas, Bed D has legumes and roots. Continue the same shift each year and the four-year cycle completes itself automatically.

Liming and Feeding in Sequence

One advantage of a structured four-year plan is that soil amendments can be built into the rotation. Add well-rotted manure or compost to the potato bed in autumn, because potatoes benefit from the richest soil and alliums will follow them the next year in that spot. Lime the brassica bed if your soil is below pH 7, because brassicas prefer alkaline conditions and lime also suppresses clubroot spores. Do not lime the potato bed — potatoes prefer slightly acidic soil and lime encourages scab disease. Let the rotation guide your feeding rather than applying the same treatment to every bed every year.

Dealing with Exceptions

Not every vegetable fits neatly into one of the four groups. Sweetcorn, courgettes, squash, and cucumbers are not strongly susceptible to the diseases that rotation targets, so they can fill any available gap without disrupting the system. Salad leaves such as lettuce and spinach are similarly flexible. Perennial crops — asparagus, artichokes, established fruit bushes — have permanent beds of their own outside the rotation entirely. The more rigidly you stick to the four main groups moving in sequence, the more reliably the system delivers its benefits.