Calibrachoa, widely known as Million Bells or trailing petunias, is a popular ornamental plant prized for its small, bell-shaped blooms that cascade from containers and hanging baskets. These plants flower continuously throughout the growing season. For gardeners interested in propagating their own stock, collecting and saving the seeds is the necessary first step. This guide provides the specific techniques required to successfully harvest and preserve the minuscule seeds from your Calibrachoa plants.
Understanding Hybridization and Viability
The majority of Calibrachoa varieties available today are the result of commercial breeding programs, developed as F1 hybrids. This hybridization means that the seeds produced often do not carry the same genetic blueprint as the parent plant. If a collected seed germinates, the resulting flower color, size, or growth habit may differ significantly from the original. The viability of seeds from these commercially produced hybrids is also frequently low, meaning fewer seeds will successfully sprout compared to non-hybrid varieties. Gardeners should view seed collection from these hybrid cultivars as an experimental process, expecting a wide range of outcomes.
Identifying Mature Seed Pods
Locating the seed pods requires careful observation, as they are extremely small and easily overlooked among the dense foliage. After the flower drops off, a tiny, green, vase-shaped structure remains at the base of the former bloom; this is the developing seed capsule.
The pod must be allowed to fully mature and dry on the stem to ensure the seeds inside are fully formed. The capsule transitions from green to a light tan or brown color as it dries out, signaling maturity. This browning stage is the narrow window for collection, as the pod is designed to split open (dehiscence) to disperse its seeds. Pods must be collected immediately once they turn dry and brown, before they burst open. Checking the plants daily, particularly in the later summer and early fall, increases the chance of finding intact, mature pods.
Step-by-Step Harvesting and Extraction
To harvest the pods, snip the brown capsule from the stem. It is helpful to work over a clean, light-colored surface, such as a paper plate or a tray, to catch any seeds that may fall out during clipping. Once collected, the intact pods should be brought indoors for final drying before extraction begins.
Spread the collected pods in a single layer on a paper towel or a small dish for several days to ensure they are completely desiccated. Once fully dry, the capsules will be brittle and easily crushed. Gently roll the dried pods between your fingers over a clean, flat surface to break them open and release the seeds. The seeds are minuscule, appearing as tiny, black specks. Carefully separate the seeds from the chaff, which consists of dried pod material and other plant debris. A fine sieve or gently blowing across the surface can help remove the lighter debris while the heavier seeds remain behind.
Proper Storage for Longevity
After extraction, the collected seeds must be thoroughly dried to prevent mold or fungus growth during storage. Even after the pods appear dry, the minute seeds can still retain moisture, so spread them on a paper towel and leave them at room temperature for an additional one to two weeks. Proper drying ensures the seeds enter a state of dormancy necessary for long-term preservation.
Once fully dried, place the seeds into a small, airtight container. Store the sealed container in a cool, dark, and dry location, like a refrigerator or a dedicated storage cabinet, away from temperature fluctuations. Label the container clearly with the collection date and the parent plant’s color or variety.