A geranium seedling is a young plant grown directly from a seed, unlike most garden geraniums (Pelargoniums) which are propagated from cuttings. Seedlings are vulnerable and require visual confirmation to ensure they are the desired plant, not a weed. Identifying these tiny plants by their distinct features is the first step for any gardener growing them from seed.
The First Leaves (Cotyledons)
The first leaves to emerge after germination are called cotyledons, or “seed leaves.” These temporary structures provide initial nourishment to the seedling and look distinctly different from mature foliage. Geranium cotyledons are typically small, smooth, and simple in shape, often appearing rounded, oval, or kidney-shaped. They usually emerge as a pair of opposing leaves, a characteristic of dicot plants. These first leaves are a light, uniform green and lack any of the scalloping or texture associated with the adult plant.
Cotyledons confirm germination but offer little information about the specific geranium variety. They are not genetically programmed to look like the mature plant, as their form is determined by the packaging within the seed itself. Once the true leaves begin to form, the cotyledons fulfill their purpose and typically shrivel or dry out.
Identifying the True Leaves
The true leaves begin to grow from the center of the seedling, between the two cotyledons, and they are the definitive feature for identifying the young geranium. They are the first structures to display the plant’s characteristic form, exhibiting the signature lobed, scalloped, or serrated edges that characterize the mature plant.
The color of the true leaves is often a deeper green than the cotyledons, and in some varieties, it may show a bluish-green or even chartreuse hue. The texture changes dramatically from the cotyledons’ smooth surface to one that is often finely textured or slightly fuzzy. Veining patterns become more pronounced, sometimes developing a subtle ring or “zone” of darker pigmentation near the center, especially in Zonal Pelargonium types.
Physical Characteristics Beyond the Leaves
Other physical traits offer additional confirmation beyond the leaves. The stem of a developing geranium seedling is often thick and sturdy, especially in Zonal varieties. The stem frequently exhibits a reddish or purplish tinge near the base and at the leaf nodes. This coloration is a common trait in the Geraniaceae family.
Many seedlings, especially Zonal and Scented-Leaved types, possess a fine, velvety, or hairy surface. These small epidermal hairs, known as trichomes, cover the stems and developing true leaves. Scented-Leaved geraniums may also emit a distinctive fragrance, such as lemon or rose, when the leaves are gently rubbed.
Early Care and Handling
Once a seedling is positively identified by the appearance of its true leaves, a shift in care is necessary to promote healthy growth. Geranium seedlings require bright light, but intense, direct sun can be too harsh for the delicate young foliage. Placing them under indirect light or a grow light for 14 to 16 hours daily encourages compact, robust growth.
Careful watering is essential to prevent damping off disease. Keep the soil surface moderately moist, ensuring the planting medium is well-draining and avoiding saturation. Once seedlings develop at least one full set of true leaves, they are ready for transplanting, often called “pricking out.” This involves moving them from the seed tray into individual containers to develop a stronger root system. A very dilute, balanced liquid fertilizer can be introduced at this stage.