The advantages of planting groups in the same family are; all the plants are related and therefore have similar requirements.
The disadvantages: they are all susceptible to the same pests and diseases.
Interplant crops which are hardier and less prone to pests and diseases randomly amongst the main crop - lettuce, alliums, cress, corn. chicory, New Zealand spinach, endive, basil.
Generally alliums should not be planted together as large plantings attract onion flies. It is better to scatter them throughout the vegetables. Leeks can be planted with onions as they confuse onion flies.
Alliums (leeks, onions, garlic, chives)- companion plants- strong smelling along with herbs –confuse pests.
Obviously there are more family groups than our 4 beds but these can be arranged to suit their growing conditions.
Leguminosae (pea & bean family) – all types of pea and bean
Brassicaceae (cabbage family) - broccoli, Brussels sprout, cabbage, kohl rabi, cauliflower, kale, mizuna, pak choi, radish, arugula, swede, turnip
Solanaceae (nightshade family) – potato, tomato, peppers, eggplant
Umbelliferae (carrot family) – celery, celeriac, cilantro, fennel, carrot, parsnip, parsley, dill
Cucurbitaceae (marrow family) – squash, zucchini, cucumber, marrow, melon, cantaoupe, pumpkin
Chenopodiaceae (beetroot family) – Swiss chard, perpetual spinach, true spinach, beetroot
Lilaceae (alliums-onions) - intercrop
Compositae - lettuce chicory endive- intercrop
Convolvulaceae - sweet potato/ water spinach- separate growing areas
Gramineae - grasses - includes maize, wheat, rice, oats, pampas grass and bamboo- some are used as cover crops although not usually in backyard veggie gardens. Corn is a member of this family and can be planted within other crops
Malvaceae - rosella, okra, cocoa-usually only grown as a few plants
Poygonaceae - rhubarb, sorrel, buckwheat- again only a few plants and more permanent so better to grow in separate areas
Ideally, to start the garden, it should be divided into separate growing areas. I’ve elected to have four because it makes it easy to keep track of rotations. Each area will have a group of plants selected by a common feature, which may be that they have the same growing requirements or belong to the same family.
Each group will occupy an area or bed for one season and then be rotated to another bed. The same process will be repeated the following season. If your available planting area is divided into 4 separate growing areas, and the crops planted as 4 groups, then each group will only occupy the same ground once every 4 years.
Some gardeners like to group their crops by what is harvested: