Crop Rotation

Crop rotation is a system where different vegetable crops are grown in the same space in sequence; either in consecutive years or within one season. For example, a cool-season crop (such as lettuce) may be grown in the spring, followed by a warm-season crop (such as tomatoes) in the summer.

Crop rotation avoids a decrease in soil fertility, as growing the same crop repeatedly in the same place will eventually deplete the soil of various nutrients. This may be prevented by following a crop that leaches the soil of one kind of nutrient with a crop that returns that nutrient to the soil. For example, legumes, such as peas and beans, have nodules on their roots which contain nitrogen-fixing bacteria and make it available for the next crop. It therefore makes good sense to alternate them with plants such as leafy brassicas or potatoes that are nitrogen-hungry.

Crop rotation is also used to control pests and diseases that can become established in the soil over time. As families of plants tend to be attacked by similar pests and diseases, regularly changing the planting location can break or limit the pest cycles. This is particularly useful for in organic gardening, where pest control is achieved without synthetic pesticides, herbicides and fungicides. For example, clubroot, which attacks brassicas and potato eelworm (nematodes) may be alleviated by rotation.

Rotation Groups

The majority of vegetables can be broken down into the four following rotation groups: