Crop Rotation Planner

How it works

The planner sorts each crop into a rotation group by its botanical family, read from its Latin name, so cabbage, kale, radish and rocket all land with the brassicas. There are four groups: legumes (peas and beans), brassicas, the potato family (potatoes, tomatoes, peppers and chillies) and roots and onions, which takes in carrots, parsnips, beetroot, the onion family and herbs from the carrot family such as parsley and dill. Lettuce, spinach, courgettes and basil have few soil-borne problems of their own, so they fill any gap. Fruit and perennial herbs, chives included, hold their ground and aren't rotated.

Each year every bed moves on to the next group, so a family comes back to the same bed only once every four years. Brassicas follow legumes, because peas and beans leave the soil richer in nitrogen for a hungry crop.

A worked example

With four beds, growing peas, cabbages, potatoes, carrots and onions, the first bed grows peas in year one, cabbages in year two, potatoes in year three, and carrots and onions in year four, then starts again. The other three beds run the same cycle one step ahead of each other, so every family is growing somewhere each year.

Fewer than four beds

With two or three beds the families still move round, but they can't be fully separated, and the planner says so. Many Scottish allotment plots are too small for a long gap between brassicas, and there the other defences against clubroot have to do more of the work: liming acid soil and improving drainage.