There are ways to improve soil health, control diseases and manage pests without applying heavy amounts of fertilizer or pesticides. For gardeners committed to growing several years into the future, crop rotation is one method to utilize.
Crop rotation, a practice widely utilized by farmers, is exactly how it sounds. It involves rotating the planting location of your fruits and vegetables across a sequence of growing seasons. How it works requires an explanation: Plants add just as many nutrients to the soil as they take from it. Rotating the location of crops allows for different nutrients to be distributed throughout your garden from year to year, helping to balance the structure of the soil.
Certain plants can introduce diseases that are soil borne. Even after that crop is harvested, they can remain in the soil. But by removing plants that host certain pests or can introduce a possibility for attracting pathogens the following season, you can help break the cycle and avoid infecting new plants of the same family or variety. Moving crops around can also make it more difficult for overwintering pests to find food when the ground thaws.
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It’s important to note that crop rotation is not a one-size-fits-all solution for boosting soil quality or ridding a garden of its diseases and pests. It’s most effective when used in combination with other applications. But there is growing evidence to support that crop rotation helps with soil health and crop yields.
Not sure how to start? Have questions? Not to worry. Follow this guide for an easy transition into the basics of crop rotation.
Organize Your Plants Into Categories
Divide your plants into groups related to their nutrient requirements and outputs. There are differing views on how exactly to do this. We suggest organizing your crops in one of two ways: by category or by plant family.
Rotating By Category
This is best for those who want a beginner option or are working with a smaller space. It involves four categories:
Legumes
Beans, peas, peanuts, lentils, green peas, chickpeas and soybeans.
Roots
Carrots, turnips, onions, beets, radishes and garlic.
Crops that bear fruit
Cucumbers, tomatoes, squash, eggplant, peppers, melons and corn. And a special addition: potatoes. (Potatoes are an exception in this category because they are susceptible to the same diseases as tomatoes, which is why they’ve been added to the fruiting group. If you have problems with potato blight, you will need to separate them out and ensure that you don’t have them follow each other in your rotation.)
Crops grown for leaves or flowers
Leafy greens such as kale and Swiss chard, lettuce, broccoli, cabbage, spinach, Brussels sprouts and herbs.
Rotating By Plant Family
If you’d like to venture out into more specialized territory, we’ve offered a further breakdown by plant family. This is feasible for gardeners with larger spaces or those who have the time to do the research on specific crop nutrient absorption and outputs.
Alliums
Chives, garlic, leeks, onions
Cucurbits
Cucumbers, melons, pumpkins, squash
Brassicas
Broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi, radishes, rutabagas, turnips
Legumes
Beans, peas, peanuts
Poaceae (grasses)
Corn
Goosefoot
Beet, spinach, swiss chard
Nightshades
Eggplant, peppers, potatoes, tomatoes
Umbellifers
Carrots, celery, dill, fennel, parsley, parsnips
Map It All Out
Before you get planting, it’s important to understand how your growing space can be used. First, make a list of the crops you’re keen to put into the ground. Then you’re going to want to draw up a diagram of your garden, containers or bed to scale and section off how much space you want to allocate for each crop. Divvy up each area based on crop category.
If you’ve chosen to group your vegetables in the four categories (legumes, roots, crops that bear fruit and crops grown for leaves and flowers) and have a smaller plot of land, you can section it off into quarters. If you’re going the plant family route, divide it into family groups, although they do not have to be equal in size; base it off of the amount in each group you’re planting. We also suggest reviewing our guide to companion planting if you’re sectioning off one area for planting. It will help you determine which crops should and shouldn’t be placed beside each other.
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It’s best to avoid slotting plants in locations where you had crops in the same group or family the year before. The further you plant a crop from its previous location, the better. Growers who have the flexibility to dig out a few smaller beds instead of using one large one should consider doing so. This will help separate your groups and allow for smoother, contained rotations that minimize risk of disease spreading or lingering in the soil.
Similarly, raised beds have the advantage of having a physical barrier between different crop families. For those with smaller spaces, using pots or planters is another option to isolate crops and provide additional space for rotation.
Plan Your Crop Rotation Direction
A full crop rotation cycle lasts three to four years. Do not plant an area with crops from the same plant family or group before that cycle is up. Follow these rotation guides, based on your initial categorization of them.
By kirpmun, Shutterstock.
Guide for Rotating By Category
For those who choose to follow groupings by legume, leaf plants, fruiting plants and roots, there’s a formula you can follow for your rotation, which is essentially centered around your legumes as nitrogen producers.
Leaf bearers should take the place of legume crops. This is because leafy crops need nitrogen and legumes are nitrogen fixers.
Your fruiting plants should take the place of your leaf plants. This is because their nitrogen needs are minor and too much can prevent them from producing fruit. The leaf crops should have sucked up enough nitrogen so this won’t be a problem.
Your root plants should take the place of your fruit plants. They need even less nitrogen.
Legumes follow root crops. This is to start the cycle all over again. Legumes also benefit from root crops because they prefer looser soil and root crops will have broken up the soil.
Guide for Rotating By Plant Family
If you decide to branch out and separate your crops based on family, it’s best to understand your crop’s nutrient needs. In addition to a few tips, we’ve indicated certain crops that feed heavily on nutrients versus lightly. It’s suggested that you follow your heavy feeders with light feeders. Nutrient builders or nitrogen fixers can then follow to replenish the soil.
Here are a few tips:
Brassicas are nitrogen hungry, so they can follow your nitrogen fixers, i.e. legumes.
Onions fare well in firmer soil left by those in the brassica family.
Peas and beans like deep, well-dug soil left over from potatoes.
Roots break up the soil, so you can follow them with potatoes, which need to grow in a deeper cavity in the soil.
Corn, tomatoes and cabbage are typically “heavy feeders.” Follow heavy feeders with legume crops to rebuild the soil.
Crops from the Umbelliferae (carrot) family are “light to medium feeders” and can follow any other group.
“Light feeders” include those in the lettuce, onion, squash-family plants as well as potatoes, most bulbs or root vegetables.
Take Stock for Future Years
So you don’t have to go through the trouble of trying to remember what was grown where over the past few years, we suggest keeping your garden maps. It will also help to make note of any pest problems you’ve had in certain areas with specific crops. This tool with University of Minnesota Extension will help you find out what the problem is if you’re unsure.
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There are also several digital tools you can use that will provide you with a few pointers for the upcoming season and also track or build a log of what you’ve planted before. This Vegetable Garden Planner is one example. Tomappo is another option for European gardeners—the app even provides personalized assistance in rotations.
If you’re planting in the ground, we recommend conducting a soil test every one to three years. This will help inform any additional soil needs for your plants. We also have a guide for soil testing if you’re unfamiliar with the process.