Geraniums are often propagated through stem cuttings, a simple method that ensures the new plant is genetically identical to the parent. Collecting and growing from seed, however, allows for a greater volume of plants and can introduce genetic variation, making it a rewarding pursuit for gardeners. This process requires attention to specific timing and technique, particularly because the seeds employ a unique dispersal mechanism that works against the collector. Successful seed saving begins with understanding which plants will yield viable seeds and progresses through careful harvesting to proper post-collection handling.
Understanding Which Geraniums Produce Viable Seeds
The common name “geranium” refers to two distinct genera, making correct identification the first step in seed collection. Popular annuals, like zonal or ivy geraniums, belong to the genus Pelargonium. Since these are often hybrids or cultivars, their seeds are frequently sterile or will not “come true” to the parent plant, resulting in unpredictable offspring.
True geraniums, or Hardy Geraniums, belong to the genus Geranium and are typically perennial cranesbills that are much more reliable for seed saving. These species varieties are open-pollinated and produce fertile seeds that resemble the parent plant. Gardeners should focus on species plants rather than named hybrid cultivars, which are often bred for sterility to maintain unique characteristics.
Locating and Identifying Seed Pods
Geranium seed pods develop after the flower fades, a process taking about two months. The developing structure is elongated, resembling a bird’s beak, which gives the plant its common name, cranesbill. The pistil swells and hardens as the seeds mature within the base.
Initially, the seed pod is green and firm, indicating the seeds inside are unripe. As the seeds mature, the long, central “bill” changes color, progressing from green to tan or dark brown. This color change, along with the drying and darkening of the seed cases, signals ripeness. The pod must be completely dry and brown before collection, but careful observation is necessary because the plant is designed to scatter its seeds quickly.
Step-by-Step Seed Collection
The greatest challenge in collecting geranium seeds is their specialized dispersal method, known as explosive dehiscence. When fully ripe, the seed capsule splits open with tension, forcibly ejecting the seeds several feet away. To prevent this loss, secure the seed pods just before they fully ripen and dry out on the plant.
A highly effective technique is to cover the developing seed heads with a small, breathable mesh bag, fine cheesecloth, or a glassine envelope. Place this enclosure over the pod when it is mostly dry and brown, but before the segments visibly split. Once covered, use scissors to carefully snip the stem a few inches below the seed head, avoiding sudden movements that could trigger the explosive release.
Move the collected seed heads indoors, place them inside a paper bag, and allow them to finish drying in a warm, dark location for several days. This allows the spring-loaded pods to dehisce safely within the bag, capturing the seeds. Afterward, gently shake the bag to separate the seeds from the remaining pod material.
Cleaning and Preparing Seeds for Storage
After the seeds are released from their capsules, separate them from the chaff, which includes dried pod remnants and feathery tassels. The actual seed is a small, hard pellet, often dark brown or black. Clean the seeds by gently rolling them between your fingers to remove any remaining husk material.
Proper drying is critical for long-term viability, as residual moisture can lead to mold and ruin the batch. Spread the cleaned seeds in a single layer on a paper plate or screen and allow them to air-dry for at least a week in a cool, dark, and dry environment. Once completely dry, place the seeds in small paper envelopes, which allow for continued air exchange.
Label the envelope clearly with the plant variety and the date of collection. For extended storage, place the labeled envelopes inside an airtight container with a desiccant, such as silica gel, to manage humidity. Store the container in a refrigerator at about 41°F (5°C). Depending on the variety, cold storage naturally provides the cold stratification period needed to encourage germination.