Crop Rotation
Gardeners don’t always think of the plants as crops, but we can certainly benefit from successful techniques on the farm. Crop rotation has been used by organic farmers for years to improve soil and plant health, improve yields and reduce pests. The benefits of crop rotation are many:
- Balances soil nutrients
- Adds soil organic matter by rotating with green manure plants
- Limits populations of soil pests and diseases
- Reduces need for pesticides and fertilizers
- Protects the watershed from excess chemical inputs
- Prevents soil erosion and water runoff
- Builds soil diversity
While the benefits are many, the technique is simple! The basic idea is to avoid planting the same type of plant in the same spot every season. Plants vary in their nutrient needs, their water requirements and their susceptibility to pests and disease. For example, tomatoes require high levels of soil nitrogen, regular water, and are susceptible to fungal wilts and nematodes. If we plant our tomatoes in the same spot every year, we are potentially depleting that soil of nitrogen, and providing the fungus and nematodes a reliable food source to grow their populations.
Instead, if we grow beans in that same bed following tomatoes, we are confounding the tomato pests — eliminating their food supply causing populations to decrease — and we are fixing available nitrogen back in to the soil.
The best way to plan your crop rotation is to organize plants by their families. Plants in the same families all have similar requirements, making them good companions to grow together and simplifying your rotation.
| FAMILY NAME | COMMON NAME | PLANTS |
| Apiaceae | Carrot family | Caraway, Carrots, Celery, Cilantro, Dill, Fennel, Parsley |
| Asteraceae | Sunflower family | Artichoke, Chamomile, Endive, Lettuce |
| Brassicaceae | Brassica family | Bok Choi, Broccoli, Brussels Sprouts, Cabbage, Cauliflower, Collards, Kohlrabi, Mustard, Pak Choi, Turnips |
| Chenopodiaceae | Amaranth family | Beets, Spinach, Swiss Chard |
| Cucurbitaceae | Cucurbit family | Cucumber, Gourds, Melons, Pumpkins, Squash |
| Fabaceae | Legume family | Beans, Clovers, Cowpeas, Peas |
| Lamiaceae | Mint family | Basil, Catnip, Lavender, Marjoram, Mints, Oregano, Rosemary, Sage, Thyme |
| Liliaceae | Allium family | Chives, Leeks, Onions |
| Poaceae | Grass family | Corn, Oats, Wheat |
| Solanaceae | Nightshade family | Eggplant, Peppers, Potatoes, Tomatoes |
The recommended rotation cycle between families is 4 years, but longer is better if you have the space!
While it is not critical to follow one family with another, it is helpful to follow heavy feeders like the nightshades and brassicas with nitrogen fixers in the legume family. In between the main growing seasons, try growing a green manure (or cover crop) like clover or oats that will hold the soil through the dormant season.
Remember, gardens are not meant to be perfect. If your space doesn’t allow for a four-year rotation, or if you only have one sunny spot to grow your tomatoes, don’t fret! Do your best to tend to the soil between seasons and rotate where you can. Your garden will thank you for it!
