Rotating garden crops to new areas each year assists in preventing disease and reduces insect pests. It may also prevent the depletion of nutrients in the soil, as each crop has its own requirements for nutrients. The standard recommendation for rotating crops uses a three-year cycle. However, there may be times when crop rotation poses difficulties and proves disadvantageous for some gardeners.
Made For Shade
For those growing vegetables in a small area, rotating large annual crops such as corn (Zea mays) or pole beans (Phaseolus vulgaris) can be difficult. These crops tend to obstruct the sunlight from smaller plants and are typically grown on the northern side of gardens while smaller crops occupy the southern side. Moving these crops to other areas in the garden means they'll cast shadows on other plants and cause unwanted shade. Small areas may not support rotation for these large plants.
In home gardens, it is not unusual for selected areas of the garden to have shallow soil. This occurs when ledges or rocky deposits rest under the garden area. In these instances, only vegetables with shallow root systems, such as lettuce greens (Lactuca sativa) and radishes (Raphanus sativus), can survive in shallow soil. Large-rooted crops such as tomatoes (Lycopersicon esculentum), potatoes (Solamum tuberosum) and corn (Zea mays) won't do well in shallow soil, so they can't be moved into those areas. This limits the gardener's ability to rotate these annual crops as recommended.
Crops such as pole beans (Phaseolus vulgaris), peas (Pisum sativum) and other vining crops are often grown on trellises or fences. Many gardeners prefer to erect permanent structures to provide support for these vegetables. Rotating these annual crops requires moving the support systems for these plants or reconstructing supports each season. Added labor and materials for these structures may be a disadvantage for crop-rotating gardeners.
Crop rotation breaks the cycle of disease between susceptible, closely related crops. But if that cycle has never started in your garden, rotation is unnecessary. In limited spaces, rotating short distances has little effect. Growing disease-resistant varieties and practicing excellent sanitation can be just as effective. Soil tests can confirm if nutrients need replenished in areas with heavy feeders. Incorporate containers to add growing room in limited garden spaces. Changing container soil annually qualifies as rotation. If disease hits, rotate by skipping the affected crops for a few years.