What is crop rotation?
Crop rotation, to put it simply, is the act of rotating the crops planted in your vegetable garden so that you do not plant the same vegetable family in a consistent location season after season. This practice has several benefits including suppressing pests and diseases, reducing soil erosion, and adding nutrients to your soil. Crop rotation can be intimidating to home gardeners, however; the benefits well outweigh the effort it takes to execute this century old practice (first documented in the Middle East in 6000 BC!)
Let's look into a few of the benefits of crop rotation:
Reduces soil erosion. Soil erosion happens when planting medium lacks aeration and improper drainage. Rotating your crops results in plants with different root structures creating channels through your soil and enhancing its ability to drain while aerating at the same time.
Limit the use of added fertilizers by utilizing nutrients already found in certain crops. "Heavy feeding" crops that need lots of accessible nitrogen (such as corn, lettuce, broccoli, tomatoes and cucumbers) should be planted in an area where "low feeders" or crops that increase soils nitrogen levels were planted the season before. (More information below in the 'The Three Feeders'.)
Suppress pests and diseases. When it comes to vegetable crops, pests and diseases are often a family affair. Broccoli and kale, for instance, are very different vegetables but they belong to the same family, so pests and diseases that plague one will often plague the other. These harmful foes can hide in your soil all Winter long, and planting a crop of the same family for them the next season is like waking them up with breakfast in bed! Instead, opt to plant a crop of a completely different family in that location the following seasons.
How often should I rotate my crops?
Ideally you can create a cycle where you rotate each family every 3 to 7 years. While that may sound like an intimidating process, you would be surprised how many vegetable families you already have planted in your garden each season (learn more about the different families below). At the very minimum one should strive to rotate every other year. If you encounter a problem with bugs or disease, this rotation should be extended to suppress the outbreak.