The Calla Lily (Zantedeschia species) is prized for its elegant, spathe-like blooms and lush foliage. While gardeners often plant rhizomes for quick results, starting Calla Lilies from seed is the method of choice for cultivating unique color varieties or breeding projects. This process demands patience, as it bypasses the rapid growth of the rhizome and typically requires up to three years before the first flower appears.
Preparing Calla Lily Seeds for Planting
Successful germination requires proper preparation of the hard-shelled seeds. If harvesting, wait until the post-flower seed capsule yellows and begins to dry completely on the stalk. The seeds are encased in a sticky, pulpy substance that must be thoroughly removed, as this material inhibits germination and promotes fungal growth.
After cleaning, soak the seeds in lukewarm water for 24 hours. This softens the dense outer seed coat, allowing water to penetrate the embryo and signal germination. To mitigate fungal pathogens like damping-off disease, the seeds can be briefly dipped in a weak solution of bleach or a commercial fungicide after soaking. Alternatively, use a fungicidal soil drench immediately after planting.
Choosing the Planting Medium and Technique
The planting environment must be sterile and optimized for drainage and warmth. The ideal medium is a fine-textured, sterile seed-starting mix, often composed of peat, perlite, or coconut coir, which ensures aeration. This mix should maintain a slightly acidic to neutral pH, ideally ranging from 6.0 to 6.5, to suit the Zantedeschia species.
Seeds are best sown in shallow trays or small pots with excellent drainage holes. The planting depth is critical: press the seeds lightly onto the surface of the moistened medium. Cover them with only a thin layer of the mix or fine vermiculite, no more than \(1/4\) inch deep. This shallow covering provides the necessary darkness for germination while allowing fragile shoots to emerge easily.
Sowing Technique and Temperature
To accommodate future growth, space seeds approximately \(1/2\) to one inch apart in the tray. Consistent bottom heat is crucial. Placing the containers on a propagation mat that maintains the medium temperature between \(70^\circ\text{F}\) and \(75^\circ\text{F}\) (\(21^\circ\text{C}\) to \(24^\circ\text{C}\)) is highly recommended.
Essential Care for Germination and Seedling Growth
Maintaining a stable, humid environment is paramount for successful germination. This is achieved by covering the planting tray with a clear plastic dome or lid. The soil moisture must be kept consistently damp but never saturated, as excess water leads to rot in the warm, enclosed conditions. Use a fine misting bottle for watering to prevent displacement of the shallowly planted seeds.
The seeds require warmth but do not need bright light until the first green shoots appear. Emergence is variable, often spanning one to three months. As soon as the seedlings emerge, remove the plastic cover and move the tray to a location that provides bright, indirect light, such as beneath grow lights or near an east-facing window.
Transplanting Seedlings
As the seedlings develop, they first produce a single cotyledon, followed by their first true leaves. Once a seedling has developed its first set of true leaves, it has established a sufficient root system. Gently transplant the seedling into its own three- or four-inch pot filled with a well-draining potting mix. At this stage, introduce a dilute, balanced liquid fertilizer every two weeks to support the rapid growth phase.