The most important garden tool is healthy soil. To grow ample harvests year after year while keeping (and building) healthy soil - rotate your crops!
What is Crop Rotation? Simply put, annual crops from different plant families play musical-garden-beds each growing season. So, a carrot growing in one bed and a tomato growing in the next in season #1 will switch places when the seeds are sown again in season #2.
Why do it? The rearranging throws pests off track (at least for a while!) and also helps return the whole spectrum of nutrients back to the soil. Crops from each plant family give and take different nutrients from the soil, so systematically switching the location of each type of crop seasonally ensures that balanced and evenly distributed soil fertility.
No matter how small or big a growing space is, there are ways to apply rotation principles in a home garden. Read on to learn more:
1. Know major families: It helps to know which major plant family each crop belongs to. This way, you can grow in family clusters and rotate by cluster each season, instead of by individual crop. For example, since kale, collards, and broccoli are all Brassicas and peppers, tomatoes, and eggplants are Nightshades, you can just switch the growing places of the Brassica and the Solanaceous crops between the first and the second seasons. The nine most popular vegetable families are:
Solanaceous, aka Nightshades: tomatoes, tomatillos, eggplants, peppers, potatoes
Cucurbits: cucumbers, summer squash, winter squash, melons,
Chenopodium, aka Amaranth family: beets, chard, spinach
Asters, aka Sunflower family: lettuce, artichokes, sunflowers, Jerusalem artichokes, escarole
Brassicas, aka Cole crops: kale, cabbage, collards, broccoli, cauliflower, kohlrabi, Brussels sprouts, radishes, turnips, mustard greens
Alliums: onions, chives, garlic chives leeks, garlic
Legumes: peas, beans
Umbelliferae, aka Parsley Family: parsley, carrots, parsnips, cilantro, fennel, celery
Grass Family: Corn, Rye, and other grains
Ideally, rotations should be made on on a three year cycle. That means, the plant family that was grown in a bed in season #1 wouldn’t be grown in that same bed till at least season #3. To keep organized, It helps to keep a garden map.
2. Keep a map and follow the soil recipe: Mapping out your garden each spring not only provides a trip down memory lane of growing seasons past, but an important record of soil history and a good system for rotations. To maintain balanced and healthy soil, it helps to follow a simple rotation recipe: Leaf, Fruit, Root, Legume. These broad crop groups each add and take away different elements from the soil. For example, legumes - beans and peas - add nitrogen back to the soil. Leaf crops - lettuce, herbs, kale - thrive in nitrogen heavy soil and don’t take away many soil nutrients, while Fruit crops - tomatoes, eggplants, squash - are heavy feeders and do best in a rich soil. Divide your garden into four sections, then grow one group per section, rotating one spot clockwise (or any consistent direction) in each consecutive season. After four years, group #1 will be grown in its original spot once again.
To read more tips on garden cartography, take a look at our article on Mapping the Garden and Choosing Seed Amounts.
3. Integrate good companionship into a small space: Growing certain crops side by side can also greatly benefit plants, while making good use of a small space. It’s a slightly different approach to rotation than rotating by one group or one plant family at a time. Perhaps the most famous and powerful example of companion planting are the Three Sisters: squash, beans, and corn. Planted together, corn provides a space for the beans to climb up; beans enrich the soil with nitrogen, which the other plants love; and squash, creeping along the ground, covers up bare soil, thus keeping in moisture, preventing weeds, and deterring some pest with its prickly vines. There are many other beneficial plant pairings that ward off pests or disease and provide structural or soil support. Take a look at our list of Garden Companions to get started.
4. Work with what you have: Rotation is especially essential in a small garden as pests and disease don’t have a lot of ground to cover to move from bed to bed or pot to pot. To create distance and order, you don’t need to grow in rows or even rectangles: just use what you already have - even minimal rotation helps. Containers can serve as markers of separate garden blocks, and potting mix should be switched out every two years (at which point the rotation cycle can be restarted). If you are growing in just one small raised bed, dividing the bed into sections (with string or plant markers) and making micro-rotations each season has many benefits for a garden’s health and longevity.