Vegetable Garden Crop Rotation
By Nate Dalman, Horticulture Researcher II
Rotation where you plant each type of crop in the vegetable garden is easily overlooked but very important. Planting the same crop in the same soil year after year can lead to major disease issues such as blight outbreaks and also depletes micronutrients in the soil. Each family of vegetable crops has specific micronutrient requirements and unique microbial activity happening amongst the roots. Rotating crops helps to balance out which nutrients are being over-used and to diversify the microbe community which improves soil health.
The way crop rotation helps to break up disease cycles is fairly straightforward. For example, if tomato blight is a problem one year but then no tomatoes are planted in the area for several years, the disease doesn’t have a host and begins to die out. Essentially the fungus that causes the disease is starved out. However, if tomatoes are continually planted there, the disease always has a host and the population of the fungus continues to grow and will cause more problems in the future.
In order to properly rotate crops you must know which plants are in which families. Rotating two crops in the same family will not produce the desired results of depriving the disease a host. Crops in each family should also be spread out and not all grouped together because that can also lead to disease issues. The main vegetable families include the cabbage, bean, onion, squash and tomato families.
Not all home vegetable gardens have the space to allow for crop rotation. When that’s the case, the best method to prevent disease and micronutrient depletion is diversifying crops. Basically, planting as many different crop types as possible and mixing them together if possible. This will help prevent an outbreak that could potentially wipe out a large portion of the garden.
In summary, crop rotation is a simple, easy and effective way to maintain a healthy and productive vegetable garden. The hardest part is remembering where you planted what in previous years. A good way to keep track is to make a map of the garden layout. After several years, the garden layouts can be reused and the cycle restarted.