Pansies, known botanically as Viola wittrockiana, are popular cool-weather flowering plants. Although often treated as annuals, these cheerful blooms thrive when temperatures are mild. Starting pansies from seed allows gardeners access to a much greater variety of unique colors and forms than typically found in garden centers, while also being significantly more cost-effective. The success of growing pansies begins with calculating the correct sowing time based on when you desire to see them flower in the garden.
Sowing Seeds for Early Spring Flowers
To achieve early spring flowers, an indoor start is necessary. Sow seeds approximately eight to twelve weeks before your average last expected spring frost date. This timing allows sufficient time for germination and growth before transplanting outdoors.
Starting seeds indoors provides the controlled environment needed during late winter months. Seedlings require supplemental grow lights once they emerge to prevent them from becoming weak. Although a heat mat can ensure initial moisture, the focus must quickly shift to providing the cooler temperatures pansies need. This ensures the plants are mature enough to be planted out as soon as the soil becomes workable in early spring.
Sowing Seeds for Fall and Winter Color
Pansies provide continuous color during autumn and mild winters. For a fall display, sow seeds during mid-to-late summer, typically in July or August. This timing is critical so seedlings can establish strong root systems before the first hard frost.
Germinating pansy seeds during peak summer heat is challenging, as high temperatures inhibit sprouting. Counteract the heat by placing sowing trays in a consistently cool location, such as a shaded area or basement, until the seeds sprout. Seedlings should be ready for transplanting about six weeks before the first expected hard frost. This allows the young plants to anchor themselves firmly, preparing them to withstand winter and produce spring blooms.
Optimizing Conditions for Seed Germination
Successful pansy germination requires specific environmental controls. The most successful germination occurs within a narrow temperature range, ideally between 60 and 68 degrees Fahrenheit (15-20°C). Temperatures exceeding 70°F (21°C) can significantly reduce or inhibit the sprouting process.
Pansy seeds require darkness during the initial germination phase. Sow the seeds in a sterile seed-starting mix and cover them completely, about one-quarter inch deep, with the medium or a layer of vermiculite. Covering the tray with dark plastic or placing it inside a closed cabinet ensures a light-free environment. Under these optimal cool and dark conditions, seeds usually begin to sprout within 10 to 20 days.
Caring for Seedlings Until Planting Out
Once sprouts appear, immediately move them from darkness into bright light. This transition prevents seedlings from stretching toward the light source, which results in weak, spindly stems. Provide light from a dedicated grow light positioned just inches above the plants for 14 to 16 hours a day to ensure stocky, healthy growth.
Proper watering is important; bottom watering is often recommended to keep foliage dry and reduce disease risk. Once seedlings develop their first set of true leaves, they can receive a very dilute liquid fertilizer. Before moving them into the garden, the seedlings must undergo “hardening off.” This gradual process involves acclimating the young plants to outdoor conditions, including direct sunlight and wind, over one to two weeks.