by Connie Oswald Stofko
“People will tell me, ‘I’ve been growing tomatoes in this same spot for 15 years and I’ve never had a problem with disease,” said Carol Ann Harlos, Master Gardener, garden writer and teacher.
“I tell them, ‘You’ve been lucky.'”
Harlos suggests that you rotate your plants in your vegetable garden about every three years to discourage pests and prevent disease. Rotating vegetables means placing them in a different spot in your garden.
An important thing to remember is that pests and diseases tend to affect an entire family of plants. When you rotate vegetables, you need to rotate them with plants from another family, she said.
For example, tomatoes, peppers, potatoes and eggplant are all in the nightshade family. If you have tomatoes in one spot, you can’t rotate them with peppers or potatoes or eggplant.
Other common vegetables planted by home gardeners are in the concurbit family. It includes zucchini and other squash, cucumbers, pumpkins, gourds and melons.
Cornell University usually recommends a three-year rotation, meaning that there will be two years of unrelated vegetables in the middle between related vegetables.
Not only does rotating vegetables help discourage pests and disease, it helps prevent soil depletion. For example, tomatoes tend to deplete the soil of nutrients, but green beans and other legumes will fix nitrogen in the soil, Harlos said. By rotating tomatoes with beans, you can keep your soil healthier.
“I never use commercial fertilizer,” she said.
If you want really detailed information on rotating vegetables, you can find a table on this Cornell page that spells out how many years you should have in your rotation for specific vegetables to avoid specific diseases. This information is aimed mainly at farmers, but some serious gardeners may find it interesting and useful.
More tips are offered in this interview on rotating vegetables in your backyard garden with Amy Ivy, Cornell Cooperative Extension horticulturist in Clinton and Essex counties.