Beets are a common garden vegetable grown for their edible roots and nutritious greens. While buying seed packets is standard, dedicated gardeners can save their own beet seeds for the next growing season. This process requires patience and a specific understanding of the plant’s two-year life cycle. Successfully obtaining viable seeds depends on managing the plant through two distinct seasons, ensuring it transitions from vegetative growth to reproductive maturity. This guide focuses on the precise steps needed to harvest and store seeds from your own beet plants.
Understanding the Beet’s Biennial Cycle
Beets (Beta vulgaris) are biennial plants, completing their life cycle over two years. The first year is dedicated to vegetative growth, forming the substantial root harvested for food. This root stores the energy reserves necessary for seed production.
To transition to a reproductive state, the beet requires vernalization—a specific environmental trigger. This is a prolonged period of cold exposure, typically requiring temperatures below 40 degrees Fahrenheit for at least ten weeks. This cold treatment signals the plant to initiate stem elongation, flowering, and seed setting in the subsequent spring and summer. Without this sustained cold, the plant remains vegetative and will not produce a seed stalk.
Preparing and Overwintering Mother Plants
The first step in seed saving is selecting the healthiest roots, often called “mother roots,” at the end of the first growing season. Choose plants that exhibit desirable traits, such as color, shape, and disease resistance. Select multiple roots, typically five to ten, to ensure adequate genetic diversity for the next generation of seeds.
The overwintering method depends on the local climate. In regions with mild winters where temperatures remain above 15 degrees Fahrenheit, roots can be left in the ground. These in-ground roots require a heavy layer of insulating mulch, such as straw or shredded leaves, to protect them from temperature fluctuations.
In colder climates, the roots must be lifted before the first hard frost. After digging them up, trim the leaves back to about an inch above the crown, taking care not to damage the central growing point. Gently brush the roots clean of soil, but do not wash them, to prevent rot during storage.
Store these lifted mother roots in a cool, dark location, such as a root cellar or cold frame. Optimal storage involves temperatures near 35 degrees Fahrenheit and high humidity (around 90 percent). Nest the roots in a ventilated container filled with a moisture-retaining medium, such as slightly damp sand or peat moss, to prevent drying out.
In the spring of the second year, replant the overwintered roots once the soil is workable. Set them in the ground with the crown just above the soil surface. Adequate spacing is necessary to accommodate the large, branching seed stalks, so plants should be set at least 18 inches apart. The stored energy in the root will then fuel the rapid growth of the flowering stalk, known as bolting, which occurs in the mid-to-late spring.
Harvesting and Curing the Seed Stalks
In the second year, the beet plant bolts, producing tall, branching stalks covered in inconspicuous, wind-pollinated flowers. Over the summer, these flowers develop into small, hard, corky seed clusters, each containing two to six individual seeds. Since the plant is indeterminate, seeds mature over a long period, with clusters at the base ripening first.
Harvest the stalks when the majority of the seed clusters have turned from green to a tannish-brown color. Wait until approximately two-thirds to 75 percent of the seeds on the stalk have matured. Harvesting too early results in non-viable seeds, while waiting too long risks losing the ripest seeds to shattering.
Cut the entire stalk near the base of the plant using shears. Move the tall stalks to a location for curing, which is a necessary drying process. Curing allows the remaining immature seeds to fully ripen and ensures a low moisture content.
Hang the cut stalks upside down in a dry, well-ventilated area, such as an open shed or barn. Protect them from direct sunlight, which reduces seed viability, and from rain or high humidity. Curing typically takes one to two weeks, allowing moisture to evaporate and the seeds to harden completely within their clusters.
Extracting, Cleaning, and Storing the Seeds
Once the stalks are fully cured and brittle, threshing separates the seed clusters from the stalk material. For small batches, run a gloved hand down the dried stalk over a container to dislodge the clusters. Larger quantities can be placed on a tarp and gently beaten to break the clusters free.
The threshed material, a mix of seed clusters and debris (chaff), must then be cleaned. Initial cleaning involves screening the material through a coarse sieve to remove large pieces of stalk. The remaining mixture is further cleaned through winnowing.
Winnowing uses a gentle air current, such as a fan, to blow away the lighter chaff while the heavier seed clusters drop into a collection container. Repeat this step until the seed lot is relatively free of debris. The final step before long-term storage is ensuring the seeds are completely dry, ideally reaching a moisture content of 7.5 percent or less.
Completely dry seeds maintain viability for the longest time. Place the cleaned, dried seed clusters in an airtight container, such as a glass jar or sealed plastic bag. Storing the container in a cool, dark, and dry location, like a refrigerator, will maximize the seed’s lifespan, which can be up to six years.