Lynne Forbragd, Extension Master Gardener in Anoka County
I grew up on a farm in northern Minnesota where my family raised cattle. The crops we grew were to sustain the cattle over winter. This consisted primarily of corn and alfalfa. Corn was harvested and chopped up into silage and the alfalfa bailed into hay. When a field where corn had been planted was ready to replant, my father would till up the soil and plant alfalfa and a cover crop of oats or wheat. This gave the alfalfa a year to mature to be bailed for hay. Once the alfalfa was depleted, he would till the soil to plant corn. By doing this method, he was creating an environment where the soil was regenerating the nutrients it needed, so less fertilizer was required, and he helped the crops resist diseases and insect infestations.
Just like farming, the soil in our urban vegetable gardens can benefit by rotating the vegetables and plants we grow each year. Our gardens are much smaller so it is even more important to adopt this practice. If one type of vegetable is planted in the same location year after year, diseases can build up in the soil which will attack the plant and decrease its’ immune system and make it more vulnerable to an insect infestation.
Plants are grouped together into plant families which have similar diseases and bugs that they are susceptible to during the growing season. Flowers and herbs are also members of the same plant families as vegetables. This provides opportunities to mix your vegetables, flowers and herbs in the same garden, and experiment to see what grows well together while adding more nutrients to your soil.
Listed are 9 families of annual plants and a small sample of the common vegetable, herbs and flowers that are in each:
Liliaceae (Lily Family) – Onions, chives, garlic, leek, tulips, daffodils, hosta, daylily
Apiaceae (Carrot Family) – Carrots, parsley, dill, fennel, parsnip
Asteraceae (Sunflower Family) – Lettuce, sunflowers, leafy greens, tarragon, marigold, mums, zinnia
Brassicaceae (Mustard Family) – Cabbage, broccoli, kale, mustard greens, radish, turnip, alyssum
Chenopodiaceae (Goosefoot Family) – Spinach, beets, Swiss chard
Cucurbitaceae (Cucumber Family) – Cucumbers, summer and winter squash, muskmelon, watermelon
Fabaceae (Pea Family) – Peas, beans, legumes
Solanaceae (Nightshade Family) – Tomatoes, peppers, eggplant, potatoes, petunia
Lamiaceae (Mint Family) – Mints, lavender, basil, oregano, salvia
Planning for crop rotation can be very simple or as complex as you want to make it. Start by keeping a yearly chart of where you plant your vegetables, herbs and flowers that you grow annually. For the next year, take the time to research the plant families to ensure that you are not planting members of the same family in the same location. You will improve your soil health and an added benefit is that you get to try to grow plants in different locations and try new designs to see what works well in your garden.