Self Seeding Plants for a Low-Maintenance Garden
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.
Managing Annual Self-Seeding Plants
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.
Dill is among the first self-seeding herbs that will show up in early spring.
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.
Bountiful Biennials Set Seeds in the Spring
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.