Crop Rotation - Control Pests and Balance Nutrients

By Ashleigh Smith

What is Crop Rotation

Crop rotation is the practice of planting a different family of crops in a given location from year to year. Vegetables can be grouped into families that share similar characteristics. For example, onions, garlic, chives, and leeks are all part of the Alliaceae family and share similar growth habits, growing conditions, susceptibility to pests, and purpose as companion plants. Crop rotation is common for large-scale farming but also for the home gardener. If you have ever had recurring issues with caterpillars, beetles, and nematodes, among other pests, then cover crops may help you avoid infestations from year to year. Utilizing crop rotation doesn’t take a lot of effort. Simply create a strategic plan ahead of time for where you will grow each crop. Then, rotate your planting location for each crop from year to year.

Why Is Crop Rotation Beneficial

The benefits of using crop rotation are seen in two areas - pest or disease control and balancing soil nutrients. Utilizing crop rotation causes a disruption in pest life cycles by physically moving the crops a given pest feeds on. When the dormant larvae emerge from the soil in the spring, they are left to find a completely different crop that they likely won’t feed on. Instead, this generation of pests die without reproducing. If you continue to grow the same crops in the same location from year to year, you will find that your pest problems begin quickly and early, causing greater damage to your crops.
farmer hold a leaf with a caterpillar
Crop rotation can also help you balance the way nutrients are used and deposited in a beneficial manner. Different crop families use different nutrients at different rates. Solanaceae plants like tomatoes or Brassicas like cabbage and kale are heavy feeders requiring plenty of nutrients for foliage and fruit development. Other families, like Fabaceae, are legumes that transfer nitrogen from the air into a usable form within the soil. By strategically organizing your crops into a rotation schedule, you can prepare a bed for heavy feeders the year before by growing a family that is a light feeder or nutrient supplier.

Crop Rotation Frequency

It is best to create a plan that takes 3-4 years for any one plant family to return to its initial starting bed. This is because of the time it can take to completely disrupt pest life cycles. The more time you can put between planting the same crop in the same location it was in before, the better. If you aren’t working in a large enough space to put 3-4 years between locations, start with rotating where possible. Just changing “planting zones” is better than continuing to grow the same crops in the same spot each year.
crop rotation example