Why a four-bed rotation earns its keep

A four-bed rotation is the simplest way to keep a small kitchen garden productive without turning vegetable growing into a military operation. Instead of trying to remember which crop followed which three years ago, you divide your growing space into four roughly equal beds and move each plant family on by one bed every year. The result is a garden that builds fertility, interrupts pest and disease cycles, and makes planning far easier. On a compact plot, where every square metre counts, that structure is worth its weight in compost.

Each family has different needs. Some hunger for nitrogen, some hate fresh manure, some suffer if they meet the same soil-borne disease twice in a row. A four-bed rotation gives every group the conditions it prefers, while giving the soil a change of pace. It also spreads your workload: one bed might need liming in autumn, another a thick mulch of well-rotted compost, another nothing but a light rake before sowing.

The four groups: what goes in each bed

The classic four-bed grouping for UK plots is legumes, brassicas, roots and alliums, and potatoes. If you don't grow many potatoes, substitute courgettes, squash or sweetcorn, but keep the same principle: a hungry, leafy crop follows a nitrogen-fixing one.

• Bed 1 – Legumes: Peas, broad beans, runner beans, French beans. These fix nitrogen from the air into little nodules on their roots. Leave the roots in the ground when you clear the crop and the next bed in the rotation gets a free feed.
• Bed 2 – Brassicas: Cabbages, kale, broccoli, sprouts, swede and turnips. These are hungry, leafy crops that appreciate the nitrogen left by the legumes. They also prefer firmer, limed soil, which helps prevent clubroot.
• Bed 3 – Roots and alliums: Carrots, parsnips, beetroot, onions, garlic, leeks and shallots. These dislike fresh manure, which can make roots fork and onions bolt. They do well on soil that was manured for a previous crop.
• Bed 4 – Potatoes: Early and maincrop potatoes, plus tomatoes if you grow them outdoors. Potatoes are useful for clearing rough ground, but they are heavy feeders and prone to blight, so keep them moving.

Rotate the beds in order: legumes, then brassicas, then roots and alliums, then potatoes, then back to legumes. Write it on a plank or keep a simple notebook. In a small garden, the whole rotation can be just four beds of 1.2m by 2.4m, with 60cm paths between them. That gives you roughly 11 square metres of growing space, enough for a family's salads, herbs and a good share of maincrop vegetables.

Setting out beds that fit your plot

Don't let perfect geometry put you off. Four beds can be raised timber frames, a grid marked out with string on a no-dig bed, or even four large containers on a patio. The key is that each bed holds one group for a full season, and that you can reach the middle without stepping on the soil. A width of 1.2m is comfortable for most adults; if you have short arms or a bad back, 1m is kinder.

• Keep paths at least 45cm wide for a wheelbarrow, 60cm if you can spare it.
• Orient beds north to south where possible so tall crops don't shade short ones.
• Group thirsty crops together to make watering quicker.
• Use the same four-bed layout each year, even if you change what you grow within a group.

Your first year: a simple sowing plan

Start in spring with Bed 1. Sow broad beans in autumn or early spring, then follow with peas and runner beans. Once they finish, sow a green manure such as field beans or grazing rye if the bed would otherwise sit empty. In Bed 2, plant brassicas from April onwards, spacing them according to the packet. Kale and sprouts can stay in until winter. Bed 3 gets carrots, beetroot and onions in succession: small sowings every three weeks give you a steady supply rather than a glut. Bed 4 takes chitted early potatoes in March, then a maincrop in April.

In autumn, clear each bed, add compost to the beds that need it, and lime the brassica bed if your soil is acidic. Leave the surface rough for the birds to pick over, or sow a green manure on any bare soil. Overwintering onions and garlic can go into Bed 3 in October or November. The following spring, simply move every group on by one bed. You'll soon find the rhythm becomes second nature.

Feeding the soil between crops

A rotation is only as good as the soil beneath it. Add well-rotted compost or manure to the potato and legume beds in autumn, but keep it off the roots and alliums bed. Brassicas appreciate a dusting of lime in winter, applied after digging but before planting. A mulch of leaf mould or spent mushroom compost around hungry crops in summer helps hold moisture. If you use no-dig methods, spread compost on the surface and let worms do the mixing. Never compost diseased brassica stems or blighted potato haulms; bin them instead.

Troubleshooting a tight rotation

Small plots rarely fit the textbook exactly. If clubroot appears in your brassicas, lengthen the rotation or grow them in large pots of fresh compost for a year. If blight strikes your potatoes, cut the haulms off at ground level and leave the tubers in the ground for a few weeks before lifting. Slugs and pigeons don't care about rotation, so use netting and night patrols. And if you only have room for three beds, group roots and alliums with potatoes and rotate three groups instead. The principle matters more than the number.

Keep a simple record: what you planted, where, and how it did. A four-bed rotation is a framework, not a cage. Adjust it, note what works, and your small plot will reward you with healthier soil and better harvests year after year.