Planting guide

Crop rotation

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.

Lettuce is not susceptible to soil-borne diseases, and can be continually planted in the same area.

Most common families

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

Other families

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

Crop rotation in practice

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:

Typical planting rotation
With four garden beds and four planting groups, a typical planting rotation could be
Brassicas / Chenopodiaceae
cabbages, beetroot, spinach
Legumes
beans, peas, cover crops
Umbelliferae
carrots, celery, parsnip, parsley
Solanaceae / Cucurbitaceae
tomatoes, eggplant, cucumber
Family group planting rotation
Other gardeners like to create planting groups based on families:
Leaves and Flowers
greens
and brassicas
Legumes
beans, peas,
cover crops
Fruits
tomatoes, eggplant, corn, cucumber
Roots
carrots, turnips,
beetroot, radish

Plant root depth

Plants which have roots close to the surface should be planted next to those which have deeper roots. Planting vegetables with different root-growth habits together will utilise nutrients from varying soil depths and thus reduce competition between the plants.
Shallow roots 
Broccoli/ Brussels sprouts/ Cabbage/ Cauliflower/ Celery/ Chinese cabbage/
Corn/ Endive/ Garlic/ Kohlrabi/
Bok choi/ Lettuce/ Onions (Leeks, Chives)/ Potatoes/ Radish/ Strawberries.
Moderate depth roots
Beans/ Beets/
Cantaloupe (Rockmelon)/
Carrots/ Chard/ Cucumber/
Eggplant/ Kale/ Peas/ Peppers/ Squash (summer)/ Turnips
Deep roots
Artichokes/ Asparagus/
Okra/ Parsnips/
Pumpkins/ Rhubarb/
Sweet potatoes/ Tomatoes/
Watermelon/ Squash (winter)
Here lettuces have been interplanted with broccoli. The broccoli has a much deeper root system than the lettuces.

They are both leaf crops which means that their nutrient requitements are similar.
Broccoli grows quite large but the lettuces will be harvested long before they would be smothered.

Some tips and other factors to consider

  • Planting by family groups could increase the risks of pests and diseases as they all attract the same problems.

  • Brassicas and leafy greens are heavy feeders and need lots of nitrogen for leaf growth.

  • Legumes ‘fix’ nitrogen in the soil so it is logical to plant brassicas and leafy greens after them. When the legume plants have finished producing, return the crop residue (the stems and leaves) to the soil to increase nitrogen levels. Legumes also stimulate beneficial soil micro-organisms.

  • Solanacae such as capsicums and tomatoes like a slightly acidic soil (i.e. lower pH). Adding compost and manures usually lowers the pH while adding lots of nutrients. If the bed has just been prepared and had compost and manure added, then plants from the Solanaceae family may be planted first. If the next crop in the rotation prefers a higher pH (more alkaline) then lime may have to be added.

  • Root crops grow well after nutrient hungry crops as they can retrieve nutrients lower down in the soil. Root crops can actually have better yields in nutrient-poor soil as lots of organic matter and nitrogen can promote root forking as well as vigorous leaf growth (instead of root growth).

  • Crops with deep roots will loosen the soil. Corn is a good crop for this.

  • Sweet corn and pumpkins like rich organic soil.

  • A green manure crop introduced into the rotation would be advantageous as these replenish nitrogen and add organic matter whilst ‘resting’ the bed (not having a crop that will be harvested and therefore depleting the soil). This may be possible between seasons, when the bed would be unproductive anyway.

  • In many areas there will be seasonal variation in the types of crops grown i.e. winter and summer crops. It is a good idea to think ahead and plan rotations around the crops you will want to be growing when those seasons come around.

  • Potatoes grow well after sweet corn. Sweet corn grows well after carrots. Plant carrots, then sweetcorn, then potatoes.

  • Consider what is known about companion planting. Try to get the best combination of crops which may benefit each other, while minimising combinations that may be detrimental to each other’s growth.
    Companion planting has its own entry in the Planting guide category of the website.

  • Two plants that both need a large amount of moisture should not be planted together as they will compete over available water.
Nightshades, like these chilli peppers, prefer acidic soil