Beets are biennials, completing their life cycle over two growing seasons. Though they can sometimes survive winter into a second year, they are most often cultivated as an annual crop for their edible roots and greens. Understanding this biennial nature is key to successful cultivation for either root harvest or seed saving.
Beets: A Biennial Plant
Beets exhibit a distinct two-year life cycle. During their first growing season, the plant focuses on vegetative growth, developing a robust rosette of leaves and a fleshy taproot. This taproot stores carbohydrates and nutrients, fueling the plant’s reproductive efforts in its second year. This initial phase is when the beet root we commonly consume reaches its optimal size and flavor.
The transition to reproductive development requires a period of cold temperatures, known as vernalization. Prolonged exposure to cool temperatures, typically between 3°C and 12°C (37°F and 54°F) for several weeks, triggers the necessary physiological changes for flowering. Following this cold period, and often with longer daylight hours, the plant will “bolt” in its second year, meaning it sends up a tall flower stalk. The stored energy from the taproot is then redirected to produce flowers and seeds, before the plant ultimately dies.
Growing and Harvesting Beets
Beets are a cool-season crop thriving in moderate temperatures, generally between 13°C and 24°C (55°F and 75°F). For a spring harvest, sow seeds directly when soil is workable. For a fall harvest, plant mid-summer through early fall. Beets prefer loose, well-draining soil with a pH between 6.0 and 7.0, and require at least six hours of direct sunlight daily for optimal root development.
To plant, sow beet seeds about 1.3 cm (0.5 inch) deep and 2.5 to 5 cm (1 to 2 inches) apart in rows spaced 30 to 45 cm (12 to 18 inches) apart. Soaking seeds for 24 hours can speed up germination, which typically occurs within 5 to 10 days. Consistent moisture is important, with about 2.5 cm (1 inch) of water needed weekly. When seedlings emerge, thin them to 5 to 10 cm (2 to 4 inches) apart for proper root development, as each beet “seed” can contain multiple embryos.
Beet roots are typically ready for harvest in 50 to 70 days when they reach 2.5 to 6 cm (1 to 2.5 inches) in diameter. Smaller beets often have a sweeter, more tender texture, while larger ones can become woody. To harvest, gently loosen the soil around the beet and pull it from the ground. Beet greens are also edible and can be harvested by snipping a few outer leaves, ensuring some remain for continued root growth.
Overwintering Beets for Seed Production
While beets are usually harvested for roots in their first year, gardeners can overwinter them for seed production in the second year. In milder climates, beet roots can be left in the ground over winter, sometimes with mulch protection. In colder regions, lift roots before a hard frost and store them in a cool, dark, frost-free location, such as a root cellar, in damp sand or sawdust to prevent dehydration and freezing.
Once spring temperatures rise, overwintered beet plants resume growth and initiate bolting. A tall stalk emerges from the plant’s center, followed by flowers that produce seed clusters. This process consumes the root’s stored energy, often rendering the root tough and undesirable for eating. Overwintering beets for seed allows gardeners to save seeds from preferred varieties, promoting self-sufficiency and preserving specific plant traits.