Rotating crops is the most important rule when planning what to grow in your veggie garden.
Rotating crops will minimize diseases, utilise different nutrients, gather nutrients from varying root depths and may benefit the following crop e.g. legumes fix nitrogen which will particularly help leafy crops.
Plants are susceptible to numerous soil-borne pests and diseases, many of which are host-specific and only infect certain types of plant. By following each crop with a totally unrelated crop means it is less likely to be infected by pests or diseases that are already present, and by removing the host plants they should either die out or move on.
A four-year or four-season rotation is advised as this time frame allows time for pests and diseases to become less of a problem.
Other benefits include:
Plants that are less prone to pests and diseases do not have to be rotated and can be planted alongside the main crop, filling in any gaps. Also inter-planting annual (or perennial if you have the room) herbs may help to combat pests as well as bringing in beneficial insects if allowed to flower.
These include: Asparagus / Beetroot / Carrots / Chicory / Corn / Cress / Endive / Garlic / Jerusalem artichoke / Leeks / Lettuce / Mint / New Zealand spinach / Okra / Oregano / Radishes / Rosemary
Perennial crops such as rhubarb, asparagus or globe artichokes can be allocated a separate area outside the rotational beds. There are cultivars available that are more resilient.
Leguminosae (pea & bean family) also known as Fabaceae –beans / peas / lentil / alfalfa / peanut / soy bean / lupin / clover
Brassicaceae (cabbage family) also known as Cruciferae - broccoli / Brussels sprouts / cabbage / kohl rabi / cauliflower / kale / mizuna / pak choy / radish / arugula (rocket) / swede / turnip / mustard / radish
Solanaceae (nightshade family) – potato / tomato / peppers (chillies and capsicum) / eggplant
Umbelliferae (carrot family) – celery / celeriac / cilantro (coriander) / fennel / carrot / parsnip / parsley / dill /cumin / caraway / Queen Anne's lace
Cucurbitaceae (marrow / gourd family) – squash / zucchini / cucumber / melons / marrow /water melon / canteloupe (rock melon/ pumpkin
Chenopodiaceae (beetroot family) – Swiss chard / perpetual spinach / true spinach / beetroot / silverbeet
Lilaceae (alliums-onions) - onions / leeks / shallots / garlic / chives / asparagus -intercrop
Compositae also known as Asteraceae- artichoke / lettuce / chicory / endive- intercrop
Convolvulaceae (morning glory)- sweet potato/ water spinach- separate growing areas
Gramineae also known as Poaceae- cereal grasses - includes maize / wheat / rice / oats /rye / barley /sugar cane / sorghum / pampas grass / 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
Polygonaceae - rhubarb / sorrel / buckwheat / Vietnamese mint - again only a few plants and more permanent so better to grow in separate areas
Rosaceae- strawberries / cherries / raspberries / blackberries / pears / apples / plums
Lamiaceae- plants that contain essential oils- the herbs- mint / basil / hyssop / lavender / sage / thyme / oregano / rosemary
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. Although another bed would be beneficial so that a green manure crop can be in an area at all times within the rotation. 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 next growing season. 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.
To offset the likelihood of insect pests or diseases coming in, inter-plant crops which are hardier and less prone to pests and diseases randomly amongst the main crop. For example carrots and onions could be planted in rows together with lettuce and radish planted around them.
We also need to factor in that some plants are seasonal, growing best in summer or winter. This means that summer crops could actually follow the winter crops thus giving two seasonal crops per bed. For example, winter Brassicas could be followed by tomatoes, cucumbers and other summer crops. There may be a period of rest between crops. This could be utilised by planting a green manure crop or just letting the ground rest after preparing the bed for the next crop.
In some areas it may be that certain crops have an extended season. Winter crops may grow for a longer period than just over winter if they are in a colder climate. Conversely some summer crops may grow for longer in warmer climates. It is also possible to create micro-climates in your growing area. Brick walls will maintain warmth and of course it is possible to make a hot house with a poly tunnel and plastic cover or cool an area down with shade cloth.
The following suggestions are just an example of how it is possible to arrange a rotation but there is really no exact format and some trial and error plantings may be necessary.
One option is to base the crop rotation on family groups.
Obviously there are more family groups than our 4 beds but these can be arranged to suit their growing conditions such as winter crops being followed by a family group that grows mid-season or waiting and planting a summer crop in the same bed for the other part of the year. This will give two or more yields in the bed each year.
Some families like the Alliums are better inter-planted with other crops and families such as the Compositae and can be used to fill up spaces . Combining two compatible families together in the one plat may be another option.
An example of this could be:
The advantage of planting groups in the same family is that since all the plants are related they have similar requirements. The disadvantage is that they are all susceptible to the same pests and diseases and may compete for nutrients and space. Companion planting (see separate section) may help to offset this.
The list of plantings in the Umbelliferae group are often not recommended to be planted together but giving them the appropriate space and nutrients and inter-plant with other crops may overcome the problems.
Generally Alliums (onion family)should not be planted together as large plantings attract onion flies. These lay eggs at the base of the plant and the larvae (maggots) attack the root . It is better to scatter them throughout the vegetables. Leeks can be planted with onions as they confuse onion flies.