Begonias are ornamental plants celebrated for their vibrant flowers and diverse foliage. While many gardeners use stem or leaf cuttings, growing them from seed is a rewarding, cost-effective method. Propagating begonias from seed requires precision because their seeds are minute. Understanding the specific nature of the seeds and the process of collection and sowing is necessary for success.
Visual Characteristics of Begonia Seeds
Begonia seeds are among the smallest in the plant kingdom, often described as dust-like or finer than sand. Their minute size makes them nearly impossible to handle without extreme care. For most common species, seeds are typically only 300 to 600 micrometers in length, meaning hundreds can easily fit on the head of a pin.
The coloration of a mature, viable seed is generally brown-to-golden, including shades of light brown, tan, or darker brown, depending on the species. Under magnification, their shape is often ellipsoidal or slightly barrel-shaped. This tiny size and light weight are adaptations for wind dispersal, necessitating special handling techniques during collection and planting.
Identifying and Collecting Seed Capsules
Begonias are monoecious, meaning they produce separate male and female flowers on the same plant. The female flower is easily identified by a swollen, often three-winged or three-lobed structure located directly behind the petals. This structure is the ovary, which develops into the seed capsule after pollination. Male flowers lack this swollen base.
To collect seeds, wait for the female flower to shrivel and the capsule to mature completely. A mature capsule transitions from green to a dry, papery texture, often turning tan or brown. Harvest the capsule just as it begins to dry but before it fully splits open, as the tiny seeds disperse instantly upon rupture.
The collection process involves clipping the dried capsule and opening it over a clean sheet of white paper indoors, away from air currents. Gently breaking the capsule releases fine dust, which is the seed mixed with chaff. Separate the seeds from debris by slowly tilting the paper, allowing the heavier, viable seeds to roll away from the lighter, non-viable material.
Sowing Techniques for Tiny Seeds
The minute size of begonia seeds dictates a specific approach to sowing for successful germination. Because the seeds require light to sprout, they must be surface-sown and should never be covered with soil or compost. Starting with a sterile, fine-textured seed-starting mix, such as a peat moss and perlite blend, is beneficial to prevent damping-off disease.
The seeds are gently scattered across the moistened surface of the medium, often using a folded piece of paper to control the distribution. After scattering, the container must be placed in a location that provides high humidity and consistent warmth, ideally between 70°F and 80°F. Covering the tray with a clear plastic dome or plastic wrap creates a miniature greenhouse environment, which keeps the surface continuously moist without direct watering.
Watering is best done by placing the container in a shallow tray of water to allow the moisture to wick up from the bottom, preventing the seeds from being washed away. Seedlings typically begin to emerge within 15 to 21 days. Once the tiny sprouts appear, the humidity dome can be gradually removed to acclimate the young plants to normal air conditions.