Crop rotation is a traditional gardening method used to reduce pest and disease problems without using pesticides. It also allows successive crops to benefit from the crops grown before.

The basic premise is that each vegie carries its own baggage in the form of pests and diseases. They also use different amounts of nutrients to grow. Some, such as legumes, even add nutrients in the form of nitrogen.

Vegies are also part of larger plant families and those in the same family may attract the same pests and diseases so crop rotation ensures that members of the same family aren’t grown in the same soil year after year. Potatoes and tomatoes for example are both classified as part of the Solonaceae family while beans and peas belong to the legume family known as Fabaceae.

By growing a particular annual crop (and other members of its family) in a different part of the garden – or a different bed in a vegie patch – it is less likely there’ll be a build up of pests and diseases specific to certain vegetables or plant families. You may also avoid depleting that bit of soil of the nutrients needed by individual crops.

To simplify crop rotation, grow vegetables in dedicated beds and grow unrelated plants in that bed in the following season. If space is small, use containers to grow some crops, changing the potting mix between replanting.

Successful crop rotation needs four to six beds. If there’s space for six beds, use one bed for perennial crops such as herbs, asparagus, artichokes, spinach, rhubarb or scarlet runner beans (which are not ‘rotated annually’) or to accommodate large spreading crops such as pumpkin and sweet potato (which can be rotated).

Even without consciously rotating crops from one bed to another, alternating between summer and winter crops, which tend to come from different plant families, provides basic crop rotation.

Simple crop rotation program

Here’s a simple crop rotation program for six beds. One bed is dedicated to permanent crops such as asparagus or herbs and another bed is used for a green manure crop or can be used to grow other crops. The following season, move the crops to the next bed taking five to six seasons for the same plants to return to their original position. Use this plan as a guide only and adapt it to suit the crops you grow.

Bed 1: Legumes (bean, broad bean, lentil, peanut, pea)

Bed 2: Leafy green vegetables (many brassicas, celery, kale, lettuce, silverbeet, spinach, sweetcorn)

Bed 3: Root vegetables (beetroot, carrot, daikon, onion, parsnip, radish) and climbers (cucumber)

Bed 4: Solanaceae (capsicum, chilli, eggplant, potato, tomato)

Bed 5: Green manure

Bed 6: Permanent (not part of rotation) or large crops (pumpkins, sweet potato, part of rotation)

Common plant families

One of keys to successful crop rotation is to be able to identify which vegetables belong to the same plant family. Here are the 13 main families of edible plants and the vegetables that belong to them.

Amaryllidaceae (onion family) chives, garlic, leek, onion, shallot

Apiaceae (carrot family) carrot, celeriac, coriander, fennel, parsley and parsnip.

Asteraceae (daisy family) artichoke, endive and lettuce.

Brassicaecea (cabbage or legume family) bok choy, broccoli, Brussels sprouts, cabbage, cauliflower, daikon, kale, kohl rabi, mustard, radish, swede, turnip

Chenopodiaceae (beetroot family) beetroot, chard, English spinach, silverbeet

Convolvulaceae (convolvulus family) sweet potato

Cucurbitaceae (pumpkin or cucurbit family) cucumber, gourd, melon, pumpkin, squash, zucchini

Fabaceae (pea or legume family) beans, broad beans, lentils, peanuts, peas

Malvaceae (hibiscus family) okra, rosella

Poaceae (grass family) sweetcorn

Polygonaceae (rhubarb family) rhubarb, sorrel

Rosaceae (rose family) strawberries

Solanaceae (potato family) capsicum, chilli, eggplant, potato, tomato