Why to Practice Crop Rotation – Even in Small Gardens

  • Difficulty Rating: Beginner
Why to Practice Crop Rotation – Even in Small Gardens

Crop rotation is a tried and true farming method that helps keep the soil healthy and pests away from our food crops.

By changing up where we plant in our annual edible gardens and how often we plant our food crops in the same place, we are more likely to enjoy higher yields with less pest and disease damage – without resorting to pesticides or herbicides.

Crop rotation refers to changing which crop is grown in which plot of land seasonally or annually. And, it doesn’t just consider a specific plant like a tomato or a cabbage. Instead, look more deeply at the family of plants each crop belongs to. For instance, tomatoes are in the Solanaceae family (aka Nightshades). This family also includes peppers, eggplants and potatoes. Cabbages, on the other hand are in the Brassicaceae family (aka Brassicas or Cole crops). This family also includes broccoli, cauliflower and Brussels sprouts. Ideally, if Nightshades are planted in a bed one year, they would not be planted in that location again for another three to seven years. (Seven is ideal, but in smaller urban gardens, three years may be the best we can manage.)

Although many beginning gardeners may have luck planting their tomatoes (or other crops) in the same “perfect” sunny spot year after year, eventually a time will come when that location will diminish in perfection. This may happen for a number of reasons.

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Many of the pests and diseases that attack our annual edible crops are able to become persistent in soils and plant waste. Pests may lay eggs in the soil below our crops where they lay in wait for the return of their favored foods the following season. Spores of decimating fungi may do the same. If we replant their favorite food in that spot year after year, we provide those pests the means of regenerating each season. However, if we instead plant a different crop that they do not favor, their lifecycle is more likely to be broken. When they hatch or germinate, if their food source isn’t present, they will either die or move on to another location.

If you do find pest or disease damage in your edible garden, it is important to identify the source of the issue. While many of these problems will be specific to one family of plants, some pests do enjoy munching on different crops and can cross from one host to another in a completely different family. Identifying the source of the issue is the best way to begin eradicating the problem responsibly and organically.

In addition to using crop rotation as a means to reduce the build-up of pests and disease in the garden, it also is a method for improving the health of our garden soils. When we grow seasonal edible crops – from leafy lettuces to crunchy cucumbers, we are planting a crop that takes a lot from the soil in which it grows.

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These plants grow rapidly, drawing significant amounts of nutrients from the ground during their rapid and short lifespan. Then we harvest and consume the plant, so none of what it has taken from that plot is returned to the earth. Even if we compost the roots from the lettuce or the spent vines from the cucumber, the location in which they have grown for a season is left more depleted of nutrients than when we put the plant into the ground. As seasonal veggie gardeners, we are therefore asking a lot from the soil. By rotating what goes into that garden bed following our harvest, we have an opportunity to give back to the soil without adding volumes of expensive fertilizer. Instead, following our seasonal edible plantings with cover crops (also known as “green manures”), we add in plants that aid in replenishing the soil.

Cover crops can add back to the soil and overall garden in several ways. Some cover crops, including those in the bean family like Fava beans, create relationships with soil fungi that take Nitrogen from the atmosphere and put it back into the soil where our next crops will find it. Plus, we can eat the Favas! Other cover crops like clover are ideal to grow while we have other nearby crops that require pollination. Not only will the clover work like Fava beans to increase the soil Nitrogen, but it will attract bees and other beneficial insects that will help increase our crop yields. Later, when our cover crops have finished their growth cycle, they may be chopped and forked back into the soil where their leafy green goodness will decompose into another source of compost to feed the soil and improve the environment for our next round of edible crops.

With a little planning to create a crop rotation plan, your edible garden – large or small – should thrive for years to come. The pests and disease affecting each region varies, so check with your local Master Gardeners, Extension office or hire a garden coach or urban farm planner to help you develop the right rotation plan for your area.