Borage (Borago officinalis) is an annual herb recognized by its star-shaped, bright blue blossoms and leaves that carry a subtle cucumber flavor. The plant is valued for its edible flowers and for its seeds, which are a source of borage oil, rich in gamma-linolenic acid (GLA). Saving these nut-like seeds allows gardeners to propagate the herb or harvest the oil-rich kernels for their nutritional benefits. The process requires careful timing and specific collection techniques.
Identifying the Right Time for Harvest
Knowing when to collect borage seeds relies on observing the plant’s transformation after flowering concludes. The vibrant blue petals will fade, wither, and drop off the stem. This signals that the plant is redirecting energy toward developing seed capsules at the base of the former flower.
Within the remaining flower structure, the seeds mature into small, hard nutlets. They change color from pale green to dark gray, brown, or nearly black. This darkening indicates the seeds are viable and ready for collection. Borage produces flowers and seeds continuously, meaning different parts of the same plant will be at various stages of maturity.
Constant monitoring is necessary because borage tends to self-sow, quickly dropping mature seeds upon ripening. This rapid shedding mechanism, known as dehiscence, means a ready seed may be on the ground tomorrow. Begin checking the plant daily as soon as the first flowers have completely faded to catch the seeds before they fall naturally.
Step-by-Step Seed Collection Techniques
Successfully harvesting borage seeds requires preparing for the plant’s quick-release habit. Because the mature, dark nutlets detach easily, place a drop cloth, sheet, or shallow container directly beneath the plant. This ensures that any seeds dislodged during collection are caught.
The stems and leaves are covered in fine, stiff, prickly hairs that can irritate the skin. Wearing gardening gloves is recommended to protect the hands during collection. Focus on sections where the flowers have dried and the dark seed nutlets are visible. While individual seeds can be plucked from the spent flower calyx, this is time-consuming.
A more efficient method is to gently cup a container around the stem or branch and lightly tap or shake the mature sections. Ripe seeds will readily drop into the container or onto the prepared cloth, while immature, green seeds remain attached. This gentle disturbance maximizes the yield of fully mature seeds without damaging the plant. If a cloth was used, carefully pour the gathered material into a single collection vessel for processing.
Cleaning, Drying, and Storage
After collection, the harvested material—which includes seeds, dried flower parts, and small stem fragments (chaff)—must be processed. First, clean the seeds by separating them from the lighter debris. This can be accomplished by lightly winnowing the material (pouring it slowly from one container to another on a breezy day) or by gently sifting it through a coarse screen.
Once cleaned, the seeds must be thoroughly dried to prevent mold and mildew during storage. Spread the dark, hard nutlets in a single, thin layer on a plate or screen in a cool, dry, and dark location, away from direct sunlight and heat. Drying typically takes between 24 and 48 hours, though larger batches may need up to a week.
The final, dried seeds should feel hard and show no sign of moisture. They are best stored in an airtight container, such as a glass jar or a sealed paper envelope, to protect them from humidity and pests. Label the container with the seed type and harvest date. Storing the sealed container in a consistently cool, dark environment, such as a basement, helps maintain the seeds’ ability to germinate for up to three to five years.