In order to avoid soil fertility, pest, and disease problems, home gardeners need to practice crop rotation, said a University of Illinois Extension horticulture educator.
"Most homeowners tend to grow the types of vegetables they like year after year," said Maurice Ogutu. "Tomatoes and peppers are some of the vegetables commonly grown by many home gardeners. Due to the limited space in backyards, the ground cannot go fallow, leading to the growing of vegetables in the same area or spot year after year.
"Growing one type of vegetable from the same family in one area for a long period of time may lead to a decline in soil fertility and higher incidences of certain insect pests and disease problems. Soil-borne disease-causing organisms tend to persist in the soil for a long period of time, and some of these organisms tend to attack vegetables from the same botanic families."
Crop rotation is a way to avoid these problems.
"Crop rotation simply means growing vegetables from different families in one area of the garden in successive years," Ogutu explained. "Crop rotation is one of the oldest cultural practices reported in several early civilizations, such as Rome and the early civilizations of Asia and Africa.
"It is a very important factor when planning a vegetable garden."
Generally, it is recommended that vegetables from the same family be rotated by growing vegetables from other families until the third year when they can be grown on the same area. The choice and sequence of crop rotation depends on soil type, climate, and rainfall. For market gardens, it also depends on marketing and other economic variables.
"Although the edible parts of vegetables may be different, botanically vegetables may belong to the same family," he explained. "In order to come up with a good crop rotation program, it is important to know different botanical families of vegetables."
Ogutu listed some of the families and their respective vegetables:
Solanacea or nightshade family--tomato, pepper, eggplant, potato, tomatillo;
Onion family--onions, garlic, leek, shallot, chives;
Cucurbit or gourd family--cucumbers, muskmelon, watermelon, squash, pumpkin, gourd;
Mustard or cole family--cabbage, broccoli, cauliflower, Brussels sprouts, kohlrabi, turnip, radish, Chinese cabbage, kale, collards, mustard greens, rutabaga;
Legume or pea family--garden pea, snap beans, lima beans, soybean;
Grass family (edible part is seed)--sweet corn, popcorn, ornamental corn;
Carrot family (edible parts are roots, leaves, and leafstalk)--carrots, parsnip, parsley, celery;
Goosefoot family--beet, Swiss chard, spinach;
Sunflower family--lettuce, Jerusalem artichoke, endive, salsify;
Bindweed family (edible part is root)--sweet potato;
Mallow family (edible part is fruit)--okra.
"It is very important to note that while home gardeners grow vegetables from just a few families or just one family such as tomato, pepper, and eggplant, it is necessary to rotate them with vegetables from other families," said Ogutu.
"This may not be applicable to home gardeners growing vegetables in containers and changing the soil at the end of the growing season."
Source: Maurice Ogutu, Extension Educator, Local Food Systems and Small Farms, firstname.lastname@example.org
Pull date: January 15, 2008