Mums, or chrysanthemums, are popular garden flowers that provide vibrant color late in the season, often well into the fall. Collecting seeds is an economical way to multiply your stock for the following year. Results can vary, especially if the parent plant is a hybrid, as the resulting flowers may not look exactly like the original. Open-pollinated or heirloom varieties offer the best chance of growing a new plant that closely resembles the parent.
Recognizing Seed Maturity
Timing is important when collecting mum seeds because harvesting too early means the seeds will not be viable. Wait until the flower head has fully dried on the stalk, which typically occurs in late fall or early winter after the main blooming period. Maturity is indicated when the petals have entirely dried, wilted, and browned.
The center of the flower head, where the seeds develop, transforms into a dry, brown seed capsule. This capsule must be completely brown and brittle, showing no signs of green or moisture, to confirm the seeds inside have reached full maturity. Waiting for this natural drying process on the plant ensures maximum seed viability.
Step-by-Step Seed Harvesting
Once the seed heads are completely dried and brown, choose a dry day for harvest. You will need clean, sharp pruning snips or scissors and a paper bag or envelope for initial collection. Snip the dried flower heads from the plant, collecting only the fully spent and brittle capsules.
Place the collected seed heads into the paper bag or a wide, shallow container. Mums are known as “seed spillers,” meaning the heads naturally break apart to release their tiny seeds, so handle the material gently. Transfer the dried heads onto a flat surface, like a baking sheet, and bring them indoors to continue drying. This initial indoor drying period removes residual moisture before separation.
Gently break apart the seed heads to release the seeds and the surrounding dry floral material, known as chaff. You can carefully crush the brittle heads with your fingers or rub them against a fine mesh screen. The goal is to separate the tiny seeds from the bulkier, dried plant material without causing damage.
Cleaning and Curing Seeds
After crushing, you will have a mixture of seeds and chaff, which must be thoroughly cleaned to improve storage life and prevent mold. The seeds are very small and can be various shades of brown. Separation can be achieved through winnowing, where you carefully pour the seed mixture from one container to another in front of a gentle fan or breeze.
The lighter chaff will blow away, while the denser seeds fall straight into the second container. Alternatively, use a fine-mesh kitchen sieve or a seed screen to sift out larger debris. Proper cleaning removes organic matter that could harbor moisture or pests during storage, which is necessary for successful preservation.
Following cleaning, the seeds must undergo a final curing process to ensure their moisture content is low enough for long-term storage. Viability is significantly reduced if seeds are stored with too much moisture, which encourages mold and rot. Spread the cleaned seeds in a single layer on a plate and let them air-dry in a cool, dark, and well-ventilated space for one to two weeks. This extended drying time helps reduce the internal seed moisture content, which prepares them for dormancy and preservation.
Optimal Seed Storage Conditions
Once the seeds are completely dry and cured, they are ready for long-term storage under conditions that mimic their natural dormant state. The three primary requirements for maintaining seed viability are cool, dark, and dry conditions. Paper envelopes are an excellent choice for storage, as they allow for slight air circulation while preventing light exposure.
Place the paper envelopes inside an airtight container, such as a sealed glass jar, to protect them from external moisture and humidity fluctuations. Labeling each envelope with the variety and harvest date is important for tracking viability, as most mum seeds remain viable for two to three years. The ideal temperature range for storage is consistently between 32 and 50 degrees Fahrenheit, often making a refrigerator the best option.
You can also include a desiccant, such as silica gel or powdered milk wrapped in a tissue, inside the sealed jar to absorb lingering moisture. Consistent temperature is more important than extreme cold, so avoid storing seeds where they will experience frequent temperature swings. Allowing the sealed container to warm to room temperature before opening prevents condensation from forming on the seeds, which helps maintain their dry state.