Learn to manage vigorous self-seeding plants and you’ll never have to buy seeds again.
A garden that produces some of its own seed is truly self-sufficient. Generally, gardeners save seeds by selecting, harvesting and storing seeds until planting time the following year. But some crops make creating a more self-reliant garden even easier, producing seeds so readily that—provided they are given time to flower, mature and set seed—you will always have free plants growing in your garden. Starting a new colony of self-seeding annuals is usually a simple matter of lopping off armloads of brittle, seed-bearing stems in the fall and dumping them where you want the plants to grow next season. It’s that easy. Most of the seedlings will appear in the first year, with lower numbers popping up in subsequent seasons. In spring, make sure you determine which seedlings are your baby self-seeders so you don’t hoe them down. Should you want to relocate your self-seeded seedlings, you can simply lift and move them—after all, they are sturdy field-grown seedlings.
Nurturing self-seeding plants is a great way to provide a diversity of flowers that supply pollen and nectar for beneficial insects. Self-seeding flowers, herbs and vegetables that show up in early spring include arugula, calendula, chamomile, cilantro, dill, breadseed poppies and brilliant red orach (mountain spinach). Nasturtiums, amaranth, New Zealand spinach, basil and zinnias appear later, after the soil has warmed.
Working with reseeding, or self-sowing, crops saves time and trouble and often gives excellent results, but a few special techniques and precautions are in order. Some plants that self-sow too freely—especially perennials such as garlic chives or horseradish—will cross the line into weediness if not handled with care.
The first group of plants to try as self-sown crops—both because they’re the easiest and they’ll be ready the same year—are those that tend to bolt in late spring. If allowed to bloom and set seed, dill, radishes, arugula, cilantro, broccoli raab, turnips and any kind of mustard produce ripe seeds in time for fall reseeding in most climates. Lettuce takes a little longer, but often gives good results in warmer areas.
You can encourage self-seeding plants by selecting a few vigorous plants from your garden plot and letting these plants grow unharvested until they bloom and produce seeds. This works well, but if you’re replanting all season, it can be bothersome to have one lone turnip holding up the renovation of a planting bed. To get around this, use a Noah’s ark approach: Set aside a bed and transplant pairs of plants you’re growing for seed into it. As the weeks pass, weed, water and stake up seed-bearing branches, but don’t harvest anything from the bed.
When seedpods dry and begin to shatter, gather and store some of the seeds as usual for replanting next year (just in case the reseeding effort isn’t successful). Shake and crumble the rest where you want the next crop to grow, and pat the soil to get good contact between soil and seeds. Or lay well-broken seed-bearing branches over a prepared bed and walk over them, which will shatter the seedpods and push the seeds into the soil. A bonus: The stem pieces serve as starter mulch. With fast-sprouting crops such as arugula, a drenching rain or good watering is all it will take to bring on a lovely fall crop.
Though many of the seeds that hit the ground will rot or be eaten, hundreds will survive winter and sprout in spring. Their strength is in their numbers. When you sow a bed of cilantro, for example, you might plant between 25 and 50 seeds. When nature is in charge, a single plant may shower your garden with 1,000 seeds.
Many annual vegetables will reseed themselves if you leave them in the garden long enough for the seeds to mature and the fruit to decompose. Annual veggies that frequently reseed and provide volunteer seedlings include winter squash and pumpkins, tomatoes and tomatillos, watermelon and New Zealand spinach.
When managing this band of garden volunteers, it’s important to ward off potential disease. The two most serious diseases of potatoes and tomatoes—early and late blights—can be perpetuated by disease-carrying plants. If you saw late blight in your garden the previous season, break the disease cycle by digging up and composting the potatoes that sprout from the previous year’s patch, along with all volunteer tomatoes and tomatillos that appear early in the season.
If you’re growing open-pollinated (often labeled OP) varieties (nonhybrid plants that grow identical to parent plants), let volunteer winter squash, pumpkins, gourds and watermelons ramble along the garden’s edge or scramble over wire fencing. Check plants weekly for signs of powdery mildew disease (white mildewy patches on fruit). Squash or pumpkin plants that show signs of powdery mildew before the fruits have set should be pulled out; don’t worry if the white patches appear later when the fruits are almost ripe. The plants will still bear a good crop.
Biennials such as open-pollinated varieties of beet, carrot, collards, kale (especially Russian strains), broccoli, parsnip and parsley produce seeds in the second year, but if you can get them through winter, you can add them to your list of self-sown crops. Cold frames or low tunnels are surprisingly effective at enhancing the winter survival of these plants.
The best time to plant biennial seeds is late summer to early fall, using the seed ark approach described at left. For example, you might grow pairs of carrots, Russian kale and parsnips together, and protect the young plants through winter with a low plastic-covered tunnel. To get prompt, strong flowering and seed production from most biennial veggies, you want to expose nearly mature plants to at least six weeks of cold soil temperatures around 40 degrees. In spring, warming temperatures trigger overwintered biennials to flower profusely, eventually producing great stalks of flowers followed by thousands of seeds—a single parsley plant may shed the equivalent of 10 seed packets. By midsummer the following year, you should have enough fresh seeds to save and scatter where you want new seedlings to grow, just in time for fall planting.
Herbs: basil, chamomile, cilantro, cutting celery, dill, parsley
Vegetables: amaranth, arugula, beet, broccoli raab, carrot, collards, kale, lettuce, orach, mustard, New Zealand spinach, parsnip, pumpkin, radish, rutabaga, tomatillo, tomato, turnip, winter squash
Flowers: bachelor button, calendula, celosia, cosmos, nasturtium, poppy, sunflower, sweet alyssum, viola
Several useful herbs and greens reseed with such abandon that they must be handled as potentially invasive. Plants behave differently depending on climate, but in general expect these crops to become obnoxious if not given appropriate discipline: borage, chives, garlic chives, edible docks and sorrels, fennel, lemon balm, horseradish and valerian. Here are the house rules:
1. Grow only as many plants as you can effectively monitor.
2. Don’t allow seeds to shed in your garden without your permission. This means pruning flowers or immature seedheads, many of which make fine cut flowers.
Adapted with permission from Mother Earth News.
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