Organic vegetable gardening is about maximizing the soil quality while minimizing pests and other problems, all without using chemical additives. One important, simple and often-overlooked tenet of maintaining a healthy vegetable garden is crop rotation.
Why rotate crops?
Rotating different types of vegetables through each section of a garden plot ensures a good nutrient balance. Various types of vegetables use different nutrients and grow to different depths, which impacts the soil structure. Crop rotation also prevents the concentration of plant-specific diseases and insects, though this may be unavoidable for some small backyard veggie plots. Even if you don’t practice strict organic gardening practices, crop rotation can boost garden productivity while reducing the need for pesticides or fertilizers.
Proper crop rotation can also keep weeds to a minimum. For example, potatoes hold their own in a weedy patch, and are easy to weed. It’s harder to reach weeds in between onions, which also often aren’t as hardy. Diligent weeding while potatoes are in a given garden section will pay off in the following year if onions go into that plot.
How to establish a crop rotation
A crop rotation schedule should be at least three years, so if you plant tomatoes in the northwest corner of the plot, they should not return to that spot for at least three years. Before starting your annual planting, list your desired vegetables for the whole season, then draw out a plan and amend the soil accordingly for each section and vegetable type.
At the end of the season, take out the plans and make notes on your successes and failures. This will help you know how to amend the soil in each section the following season.
Families of vegetables
Most vegetables belong to families that need the same nutrients and fall victim to the same predators, but the connections are not often obvious. Here is a quick guide to vegetable families:
• The large and diverse cabbage family also includes arugula, broccoli, Brussels sprouts, cauliflower, kale radishes and turnips. They need firm, moist soil, and should follow the nitrogen-fixing bean family.
• The onion family also includes garlic, leeks and shallots. They need well-drained soil, and they can follow potatoes or cabbages without necessarily requiring new organic enhancements.
• The squash family also includes zucchini, watermelon and cucumbers. They can be grown alongside cabbages and potatoes, and need a good dose of compost before planting. Most of these plants are good at blocking weeds, so can be planted strategically.
• Many peas and beans are in the same family. They can be planted after potatoes, as they use many of the same nutrients, but before cabbages, as they will fix nitrogen for these plants.
• Beets are related to chard and spinach. Like cabbages, they like wet, fertile soil.
• By contrast, lettuces and artichokes like well-drained soils. Also keep in mind that lettuce is very fragile and prone to attack from diseases and pests. Make sure it is easy to reach, and not covered by other plants that may harbor lettuce’s enemies.
• Perhaps the most diverse and odd family combines potatoes, tomatoes, peppers and eggplants. Though the fruit varies widely, they all have similar flowers. They like fertile, compost-rich soil.
• The carrot family is another diverse clan united by its flowers. It includes celery, parsley, parsnips and fennel. These are generally pretty hardy, and can thrive in the remnants of additives that were used for cabbages or other needy plants.
Several plants don’t fit any of the above categories, making them versatile enough to fill any holes in the garden plan. They include sweet corn, buckwheat and New Zealand spinach. On the other hand, consider planting designated permanent beds for perennial rhubarb and asparagus.
Crop rotations can also be used in a greenhouse, though the tight space may make a good rotation tricky. Instead of trying to rotate crops around the greenhouse, consider skipping certain varieties for a season.
Following a simple crop rotation schedule is an important piece of the organic gardening puzzle. Also use healthy, compost-rich soil; make smart plant selections; practice companion planting; and provide a welcoming habitat for lady beetles and other beneficial insects that get rid of unwanted pests. For more information, consult “Rodale’s Illustrated Encyclopedia of Organic Gardening,” which provided some of the information in this article.