Crop rotation is perhaps the single best way to fight disease and pest problems that can plague your vegetable crops. Ideally, you will have several separate areas, beds, patches, or sections in your garden so that you can rotate your crops around in order to prevent the same crops from being repeatedly grown in the same place. This also gives your soil a chance to recover each season.
It’s not enough just to rotate crops…you need to know which crops belong to the same family. For instance, garlic and leeks belong to the same family. They attract the same pests. You don’t want to plant garlic in Patch A one year, then leeks in Patch A the next year. No, you need to rotate the entire family.
Remember from high school biology class the kingdom-phylum-class-order-family-genus-species way of classifying all living things? Plant families are grouped together in the following manner:
• Alliaceae – the stuff that makes your eyes water: all varieties of onions (which includes chives and leeks), garlic, and that pungent garlic-onion hybrid known as the shallot.
• Amaranthaceae – beets, and leafy greens such as spinach and Swiss chard.
• Apiaceae – root vegetables such as carrots, celeriac (and its celery stalk), and parsnips; the herbs cilantro, fennel and parsley.
• Asteraceae – artichokes, sunflowers, and salad fixins: endive, escarole, lettuce, and radicchio.
• Brassicaceae – broccoli, Brussels sprouts and all cabbage varieties, cauliflower, leafy greens such as arugula (also known as salad rocket), collard, kale, and mustard; root vegetables such as radishes, rutabagas, and turnips.
• Cucurbiticeae – cucumbers, all melon varieties, all summer and winter squash varieties (including pumpkin).
• Fabaceae (or Leguminoceae) – all varieties of beans and peas, jicama, and peanuts (no, they’re not nuts!).
• Solanaceae – bell and chili peppers, eggplant, potatoes, tomatoes, and tomatillos. Interestingly, the sweet potato, though a member of the same order, has a different family classification – convolvulaceae.
Well, now that you have a list of the plant families (and you’ve learned a few Latin phrases to dazzle your friends with), start sketching out a long-term crop rotation schedule. See if you can go out as far as five years without planting the same family in the same space twice. Ideally you should be able to go at least three years.