Scabiosa, commonly called Pincushion Flower, is a desirable garden plant prized for its unique, dome-shaped blossoms and long bloom period. Both annual (Scabiosa atropurpurea) and perennial (Scabiosa caucasica) types are grown, offering a variety of colors and heights. Starting these flowers from seed is a cost-effective way to fill your garden, provided you follow a precise schedule and method.
Timing the Sowing and Seed Preparation
The timing for sowing Scabiosa seeds depends on whether you start them indoors for an earlier bloom or direct sow them. For an early summer display, start seeds indoors four to ten weeks before the last expected spring frost. This method allows the plant to establish a robust root system before transplanting.
Direct sowing should only be attempted after all danger of frost has passed, resulting in a much later bloom. Scabiosa seeds generally do not require specialized pre-treatment like cold stratification or scarification. They are ready to sow directly from the packet, though some gardeners briefly soak them.
Sowing Techniques and Germination Requirements
Use a sterile, fine-textured seed-starting mix in clean trays or small pots to prevent fungal diseases. Scabiosa seeds are small and should be sown shallowly; some varieties require light to germinate. Press the seeds gently onto the surface of the moistened soil or cover them with only an eighth to a quarter-inch of the starting mix.
The optimal temperature for sprouting is consistently between 65°F and 70°F. Maintaining uniform moisture without saturating the soil is important, often achieved by misting or bottom watering. Germination typically occurs within five to twenty-one days. Covering the tray with a clear dome helps maintain necessary humidity and temperature stability.
Caring for Young Seedlings
Once the first tiny green shoots appear, which are the cotyledons, the environment must immediately shift to provide intense light. If a south-facing window does not provide enough bright, direct light, supplemental grow lights should be positioned three to four inches above the seedlings for 16 hours each day. Adequate light prevents the young plants from becoming weak and leggy.
The watering regimen must be adjusted to allow the surface of the soil to dry slightly between waterings, reducing the risk of damping-off disease. Once the seedlings develop their first set of true leaves, they should be thinned to one plant per cell or pot to prevent overcrowding. The true leaves indicate the plant is ready for the next phase of growth. About four weeks after germination, a diluted liquid fertilizer can be introduced to support robust growth.
The final step before outdoor planting is a process known as “hardening off,” which prepares the tender indoor-grown plants for the harsher outdoor environment. Over a period of seven to ten days, gradually expose the seedlings to increasing amounts of direct sunlight, wind, and temperature fluctuations. Begin with just a few hours in a sheltered, shaded location, bringing them in at night, and slowly extend the time and exposure until they can tolerate a full day outside.
Moving Scabiosa Outdoors
Transplanting your young Scabiosa plants into the garden occurs after the hardening-off period is complete and all risk of frost has vanished. The permanent location should offer full sun for the best performance, although partial afternoon shade is tolerable, especially in hotter climates. Scabiosa prefers well-draining soil that is rich in organic matter.
When planting, carefully remove the seedling from its container, disturbing the root ball as little as possible to avoid transplant shock. Place the plant in the prepared hole at the same depth it was growing in the pot. Space individual plants 9 to 15 inches apart to ensure good air circulation, which helps prevent issues like powdery mildew. After setting the plants in the ground, give them a deep, thorough watering to settle the soil and encourage establishment.