Crop rotation for growing vegetables

What is crop rotation?

Essentially different vegetables are grouped into families and each growing season you plant each 'family' of vegetables in a different position in the garden.

What are the families?

Root crops; carrots, beetroot, parsnip, onions, garlic, leeks etc

Brassicas and greens; cauliflower, broccoli, cabbage salad greens, lettuce, spinach, silver beet etc

Fruiting vegetables; tomato, potatoes, cucumber, pumpkin, courgette, corn etc

Legumes; peas & beans

Why do we practice crop rotation?

Different 'families' have different nutritional needs and different pests / diseases that affect them.

Planting the same plants in the same spot year after year increases the chance of disease and pest building up in that spot. Planting in different spots each year limits the spread of disease in particular. 

Plants using the same nutrients each year can lead to deficiencies in the soil.

The legume family actually draws nitrogen from the air and stores it in nodules on their roots. If you leave the roots in the soil to rot down after harvest, the nitrogen is released for the next crop to use. If you remove the roots with the plant, the nitrogen will be lost.

How do I carry out a crop rotation?

It is recommended that you keep track of what you plant each year so you can keep track of your rotation. Keep the zones well separated if possible. You will need the same number of zones or beds as the years in your rotation.

Zone 1- Legumes

Zone 2 - Brassicas/Greens

Zone 3 - Fruiting Veges

Zone 4 - Root veges

The following year, Legumes are planted in Zone 4 and the other 3 families move up into the zone before them. The families move through each of the zones over the 4 years and in the 5th year, the legumes are back to zone 1.

If space is an issue in your garden, you can always incorporate container growing into your plan so you can have more zones that you can rotate plants through. Container growing also has the benefit of starting with fresh potting mix if you have had a particularly bad year with pests or diseases.

Why are they rotated this way?

Year one/ Zone one- Legumes. They fix nitrogen into the soil and help improve the soil structure. 

Year two/ Zone one - Brassicas/Greens. They need plenty of nitrogen and use up most of what the legumes leave behind.

Year three/ Zone one -Fruiting Veges. They need some nitrogen along with phosphate and potassium.

Year four/ Zone one- Root veges. They need more phosphate and potassium than nitrogen.

Year five/ Zone one - back to legumes to replenish the soil with nitrogen.