Calendula officinalis, commonly known as pot marigold, is an easy-to-grow annual flower popular for its medicinal and culinary uses. Saving the seeds is a simple, cost-effective way to ensure a continuous supply of blooms and preserve the traits of a favorite variety. This process allows gardeners to bypass purchasing new seed packets each year. The following steps detail the proper techniques for collecting, drying, and storing calendula seeds for successful germination.
Identifying and Harvesting Mature Seeds
The timing for seed collection is centered around the plant’s natural life cycle, specifically when the flower heads have completely faded and dried out. Stop deadheading spent blooms toward the end of the summer or in early fall to allow the seed heads to mature on the plant. A mature seed head transforms from a green, soft state into a papery, brittle texture.
Look for the protective involucre, the green base of the flower, to turn light brown or gray. The seeds themselves are long, curved, and will change from light green to a deeper shade of brown or gray. They should be easily dislodged from the flower head with a gentle touch, indicating they are fully dried and ready for harvest.
Harvest on a dry day, ideally after morning dew has evaporated, to reduce moisture content. Use sharp shears to snip the dried seed heads from the stem. Alternatively, gently rub the dry seed heads between your fingers to collect the seeds directly into a container. Collecting the entire dried head is often easier, as separation can be completed indoors later.
Essential Drying and Cleaning Techniques
Proper drying is the most important step to prevent mold and rot during storage, which are the main causes of seed viability loss. After collecting the seed heads, spread them in a single layer on a fine-mesh screen, a paper towel, or a sheet of paper. Place this material in a dry, well-ventilated location that is out of direct sunlight.
Allow the seeds and accompanying plant material, known as chaff, to dry completely for about one to two weeks. The seeds are fully dry when they are brittle enough to shatter or snap rather than bend or crumple. Once dry, the next step is cleaning, which involves separating the curled seeds from the lighter, flaky chaff.
To clean a small batch, rub the dry flower heads gently between your hands over a bowl. Then, carefully blow away the lighter chaff while the heavier seeds remain. While cleaning is ideal for long-term storage, a small amount of remaining chaff will not harm germination. Ensuring zero residual moisture is paramount before proceeding to the final storage stage.
Proper Storage for Long-Term Viability
Successfully dried calendula seeds must be stored under specific environmental conditions to maintain their germination potential for multiple seasons. The three most important factors for seed storage are coolness, darkness, and dryness. A consistent temperature, such as that found in a closet or basement, is ideal, as temperature fluctuations can prematurely shorten the seeds’ viable lifespan.
For containers, choose materials that protect the seeds from moisture and light, such as small paper envelopes, glassine bags, or airtight glass jars. Paper envelopes are a common choice because they allow for some air exchange, while a sealed container can benefit from the addition of a desiccant packet to absorb any residual moisture. Regardless of the container, you must label it clearly with the variety name and the date of harvest.
Calendula seeds typically remain viable for at least one to two years when stored correctly, though they may last longer under optimal conditions. Storing the seeds in a consistently cool, dark, and dry environment helps mimic their natural dormant state, maximizing the window for successful planting next season.