Crop Rotation: The Simple, Time-Tested Secret to Bigger Harvests and a Healthier Garden

This simple but powerful technique improves soil health, reduces pests and disease, and creates a more sustainable garden.

Raised garden beds, ideally in a multiple of four, make it easy to rotate crops between beds each year. Mariana Serdynska/Shutterstock

Have you ever wondered why those tomatoes that did fabulously the first year were less productive in the second year and are downright struggling in the third season?

Planting the same plant in the same location for multiple seasons depletes the soil of the particular nutrients the plant in question needs to thrive. It also allows for a buildup of plant-specific insect pests and soil-borne pathogens that will increase each year.

Yes, all this can be somewhat mitigated with diligent use of fertilizers and pesticides, but why go to all that expense and effort when there’s a simpler solution that has worked for centuries? The concept of crop rotation is simple: Each season, change the location of common vegetables in your garden.

This is ideally done on a three-year (good) or four-year (ideal) cycle, but if that’s not possible, just doing the best one can is still helpful.

Family Matters

Not planting tomatoes in the same location year after year may not be enough. It’s important to understand that plants are not individuals, but part of an herbaceous family.

For example, tomatoes are part of the Solanaceae (nightshade) family, which means that they cannot be followed by any of their relatives—sweet and hot peppers, eggplants, tomatillos, ground cherry, husk cherry, and potatoes—as they deplete the soil of the same nutrients and are susceptible to the same pests and diseases.

Here are a few other common backyard garden families:

• Fabaceae (Leguminosae) family: all beans and peas.
• Brassicaceae (mustard) family: broccoli, Brussels sprouts, cabbage, cauliflower, Chinese cabbage, bok choy, collards, kale, kohlrabi, mustard greens, radish, rutabaga, and turnip.
• Apiaceae/Umbelliferae (carrot) family: carrots, celery, parsnips, and parsley.
• Cucurbitaceae (cucurbits) family: all types of squash, cucumbers, melons, and pumpkins.
• Alliaceae (onion) family: all onions, garlic, chives, leeks, shallots, and scallions.
• Amaranthaceae (amaranth) family: spinach, beets, and chard.
• Poaceae (grass) family: popcorn and sweet corn.
• Asteraceae (sunflower or daisy) family: sunflower, endive, lettuce, and salsify.

Tomatoes, part of the nightshade family, are "high feeder" crops. eugenegur/Shutterstock

Rotate Right

The ideal backyard crop rotation system has a minimum of four raised garden beds (or a multiple of four). These can be easily rotated each year to keep the soil from being depleted.

An alternative is to plant in four distinctly separate areas of the backyard, or to section off a large single garden space into four distinct areas with pathways that separate the plant types and make it easier to maintain and harvest the garden.

A sample spring plan would be to plant early season potatoes in bed one, legumes in bed two, brassica in bed three, and root vegetables in bed four. The following year, everything would shift over one zone: Potatoes should now be planted in bed two, legumes in bed three, brassica in bed four, and root vegetables in bed one. In year three, you would shift the planting over one more bed, and again in year four. In year five, the plant types should be back in the original beds.

These early-season crops could be followed by nightshades in bed one, legumes in bed two, cucurbits in bed three, and leaves or okra plants of your choice in bed four. Rotate yearly as above.

3-Year Plans

Four-year plans allow pests and pathogens more time to dissipate from the soil, but three-year plans are also an option.

Typical three-bed rotations may include Solanaceae/Cucurbitaceae, Fabaceae/Alliaceae, and Brassicaceae, for example. Other gardeners opt for alternating root vegetables, leafy crops, and fruits such as tomatoes, squash, corn, or beans. The process can be refined over time.

One way to replenish soil nutrients quite efficiently is to rotate high feeders (tomato, corn, squash) with low feeders (carrots, spinach, beets) and givers (legumes, which add nitrogen and other good things to the soil).

It all comes down to what one has in the garden and following the golden rule of not planting the same plant in the same space in succeeding years.

Legumes are "giver" crops that replenish the soil with nitrogen and other beneficial nutrients. CTatiana/Shutterstock

Green Manure and More

More sophisticated crop rotation plans can include using cover crops (green manure) or even leaving the ground fallow.

Cover crops offer many advantages, from adding nutrients to the soil to simply keeping soil from drying out and being blown away in the offseason. They can simply be tilled under when you’re ready to plant crops again.

But be careful, as they may be in the same family as the plants being rotated. If they are, remember the rotation rule: No plant family should be planted more than once every three to four years. Happily, three common winter ground covers—winter rye, oats, and barley—are in the Poaceae family, so they’re probably fine as long as one is not planting corn.

Leaving an area fallow allows it to rest, but fallow ground is prone to erosion and weeds. Instead, consider covering the garden with a thick layer of mulch, landscape fabric, or even cardboard when not in use.

Cover crops keep soil from drying out and being blown away in the off-season, while also adding nutrients. Khemphon khounpasirth/Shutterstock

Speaking of Weeds

Seasoned gardeners know that diligent weeding is important, as weeds steal valuable moisture and nutrients from vegetable crops. Those green annoyances can also belong to some of the same plant families as the vegetable crops, acting as hosts for pests and helping harbor soil-borne disease while undoing the hard work of proper crop rotation. Get pulling!

Easy Errors

The most common mistake made in crop rotation is under-rotation—replanting a plant or plant family too soon. Keep diligent records; a garden journal or seasonal photos will give you something to refer back to.

Be Realistic

Crop rotation will help make plants healthier and harvests more abundant, but it is not a cure-all. Amend soil with compost between plantings and fertilize plants as directed, particularly heavy feeders such as tomatoes. Occasional pest remediation may be needed as well.

Don’t Forget Nitrogen

Through a symbiotic relationship with bacteria in their root nodules, legumes begin adding valuable nitrogen into the soil as soon as they are planted. Even if beans aren’t high on the dinner menu, the plants that follow them will enjoy the “meal.” Plus, most dry easily for prepper storage.

Keep Things Friendly

Allelopathic plants produce chemicals that can suppress the growth of other plants in their vicinity. The next crop may be affected if it is planted before the chemicals dissipate. The exact effects depend on the species; for example, sunflowers inhibit the germination and growth of lettuce, while turnips can stunt seed germination for any succeeding plants. Do some research.