Gardening is rarely a one-off proposition. Once you taste and share your homegrown herbs and vegetables, you’ll want to grow them every season possible, year after year. After a few years of vegetable gardening, however, you might notice that you have diminishing returns; the tomatoes aren’t quite as productive or maybe the squash are prone to disease.
The answer is simple: It’s likely that the soil is worn out and depleted because the same heavy-feeding crop is planted in the same place each year. Employ the principle of crop rotation to put the bang back in your garden.
Vegetable gardening takes a lot of nutrients out of soil, and certain kinds of plants can bring diseases and attract pests. For this reason, you’ll want to rotate your crops to keep edibles at their best year after year. When you rotate crops, you interrupt the life cycle of certain pests and diseases and allow the soil to replenish. This organic technique will improve your gardening by keeping the soil fertile and discouraging plant disease and insect problems.
For example, tomatoes and corn are heavy feeders that will deplete the soil of nitrogen and phosphorus. Planting tomatoes in the same place each year will result in reduced crop yields and more susceptibility to disease and pests. By moving tomato plants to different parts of the garden each year, the soil will recover more quickly.
Crop rotation is a principle of large-scale farming and gardening, but the method can be incorporated in smaller home gardens by planning, either online or on paper in a garden journal. Group the vegetables in the garden according to their families — root vegetables, legumes and fruiting plants (see list below). With each year, move the different families throughout the garden.
How to Make a Crop Rotation Plan
To make a crop rotation plan, draw out your garden into blocks, then label each block according to families. Next year, move the families clockwise in the plan. Aim for at least three years, and preferably four, before returning a plant family to its original plot.
Know the plant families
- Nightshades: tomatoes, peppers, eggplant, potatoes
- Carrot: celery, parsley, parsnip
- Goosefoot: beet, spinach, Swiss chard
- Gourd: cucumber, muskmelon, pumpkin, summer squash, watermelon, winter squash
- Grass: ornamental corn, popcorn, sweet corn
- Mustard: broccoli, Brussels sprouts, cabbage, cauliflower, Chinese cabbage, collard, kale, kohlrabi, mustard greens, radish, rutabaga, turnip
- Onion: chives, garlic, leek, onion
- Pea: bush bean, kidney bean, lima bean, pea, pole bean, soybean
- Sunflower: endive, lettuce, sunflower
Consider Cover Crops
Sometimes, you may have a need to leave a block of your garden fallow, that is, without a crop. In this case, use a cover crop or green manure to improve the soil. Fallow land can become weedy or erode, but when you use a green manure that is then turned under, you improve the soil structure and add nutrients back into the soil.
A cover crop is usually a legume because they take nitrogen from the air and fix it into the soil. When you use a mix of legumes and non-legumes like a grass or grain, the soil gets the benefit of the nitrogen and decaying plant matter. Warm-season cover crop options are soybeans, cow peas, buckwheat and sorghum. Crimson clover and rye are used in fall and winter.
As a sustained practice, cover crops will improve your garden year after year. Cover crops are turned into the soil in the next season, preferably just after they flower so that the seeds are not set. Down the road, those seeds could become weeds. Learn more about cover crops like ryegrass.