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Practicing crop rotation in your vegetable garden improves the soil and helps control diseases, insects, and weeds—reducing the need for harmful synthetic pesticides.

How to practice crop rotation

With crop rotation, vegetables in the same botanical family are planted in a different part of the garden from one year to the next. With short-season crops, planting different successive crops in a bed during a single growing season is another form of crop rotation. Practicing crop rotation:

• Improves soil fertility and soil structure
• Helps control diseases and insects that attack a particular plant family
• Helps control weeds
• Increases yields

Vegetables that belong to the same botanical family have similar nutrient requirements. Some are “heavy feeders,” which use up more of the soil’s minerals, while others are “light feeders” that use up fewer minerals. There are also plants that improve the soil, actually adding nutrients. Alternating these three types of crops in a single plot maintains healthy soil. Heavy feeders include broccoli, cabbage, corn, cucumbers, squash, and tomatoes. Light feeders include carrots, onions, peppers, potatoes, and Swiss chard. Soil builders include peas, beans, and other legumes.

Common rotations

There are many different methods of crop rotation. Although a four-year rotation schedule is most common, some experts recommend a three-year rotation for home gardens. Common rotations include:

• Heavy feeders, light feeders, and soil builders (legumes)
• Roots, brassicas, and all other crops
• Potatoes, brassicas, legumes, and roots
• Legumes; onions, carrots and tomatoes; and brassicas

For example, in the third rotation above, plant potatoes in the plot the first year. The second year, plant brassicas. The third year, plant legumes. The fourth year, plant roots.

While there are many rotation choices, one rule in virtually all rotations is to plant brassicas in a different spot each year. Brassicas are heavy feeders and are all are susceptible to a fungal disease called clubroot. While clubroot can persist in the soil for up to 20 years, crop rotation helps slow the spread of club root spores. For more information on clubroot and other plant diseases, see "Use natural disease control." Brassicas include broccoli, brussels sprouts, cabbage, cauliflower, collards, kale, mustard, rutabagas, and turnips.

Planning crop rotations

Start by learning the botanical families of common garden vegetables . Then list the vegetables you want to grow, grouping them by botanical family.

Rotating crops is easier if you divide your garden into beds of roughly the same size. If you plan to use a three-year rotation, divide the garden into a number of beds that is a multiple of three. Grow vegetables in the same botanical family, with the same growth requirements, in the same bed. If you don’t have enough of a single crop to fill a particular bed, combine crop groupings with compatible needs. Leafy greens and shallow-rooted vegetables that are not members of the primary plant families used in crop rotation can be planted to fill in spaces. Draw a plot plan of your garden every year, showing what was planted where, to keep track.

Crop rotation doesn't have to be complicated. Start by remembering one simple rule: don’t plant the same crop in the same spot two years in a row. Even in a small garden, you can still use the principles behind crop rotation to improve your soil and your yields: just divide the garden into smaller beds than you would in a larger garden.

Here are a few simple rules for successful crop rotation:

• Group crops according to susceptibility to the same insects and diseases.
• Alternate root vegetables with shallow-rooted vegetables to improve soil structure.
• If you practice interplanting (combining different vegetables in the same bed), use the main crop in your rotation plan.
• Don't plant tomatoes and potatoes to follow each other: they're both in the nightshade family.
• Plant brassicas and leafy greens to succeed legumes: they like the added nitrogen.
• Don't plant carrots or beets in direct succession to a legume.

Practicing crop rotation helps you go green because…

• It decreases insect pests, lessening the need for insecticides.
• It decreases vegetable diseases, lessening the need for fungicides.
• It adds nutrients to the soil.
• It improves soil structure.

Both the Irish Potato Famine and the devastating Dust Bowl are linked to one crucial mistake: monoculture. Monoculture is the growth of a single crop on the same piece of land season after season.[1] During the Dust Bowl, which was caused by a combination of drought and poor soil, nutrient-leeched soil blew across the countryside and families were driven from their homes. During the Potato Famine, a single variety of potato, which did not have resistance to potato blight, was grown on the same land year after year. These disasters could have been prevented by using crop rotation.[1] The same crop cannot be grown continuously on the same piece of land year after year without causing serious damage and serious problems. [2]

Prior to the 1950s, crop rotation was commonly practiced to maintain fertile soil. When synthetic fertilizers came into use, however, farmers began practicing monoculture—growing one type of crop—and relying on chemical fertilizers to replace depleted nutrients. This worked in the short term, but over time synthetic fertilizers took a toll on soil fertility. While most farmers practice crop rotation today, they often use a short rotation of only two or three years.[3]

Pasture and cropland occupy 50 percent of the earth’s habitable land and provide habitat and food for the majority of the world's plant and animal life. Soils managed by farmers (and on a smaller scale, by gardeners) are integral to ecological processes like conserving and filtering water and sequestering carbon. Agricultural practices affect the planet's supplies of fresh water, clean air, healthy soil, and biological diversity. [2]

Crop rotation is one of the most simple yet effective types of control for diseases and insects that have a single generation each year. When a crop is grown in the same spot season after season, insects and disease organisms can become established in the soil. This can result in a more rapid infestation of pests each year. Rotating even a short distance from the previous site can help to deter, delay, or avoid damage.[4]

Glossary

• brassica: a member of the mustard family (of the genus Brassica) including broccoli, brussels sprouts, cabbage, cauliflower, and turnips.
• crop rotation: the practice of growing different crops in succession on the same land chiefly to preserve the productive capacity of the soil.
• heavy feeder: a crop which depletes more of the soil’s minerals, such as broccoli, cabbage, corn, cucumbers, squash, and tomatoes
• interplanting: combining different vegetables in the same bed.
• legume: a member of the Fabaceae or Leguminosae family of plants, including peas, beans, peanuts, lentils, chickpeas, and soybeans.
• light feeder: a crop which depletes fewer of the soil’s minerals, such as carrots, onions, peppers, potatoes, and swiss chard.
• monoculture: The growth of a single crop on the same piece of land.

External links

• Texas Agricultural Extension Service - Vegetable Rotations, Successions and Intercropping Learn more about crop rotation in the home vegetable garden.
• Iowa State University - Crop Rotation in the Vegetable Garden Learn the botanical families of common garden vegetables.
• Care2 - Crop Rotation
• The Gardener's Network - Crop Rotation