Impatiens, often called Busy Lizzies, are popular annuals known for delivering vibrant color in shady areas. Starting them from seed is an economical way to produce many plants for garden beds, containers, and hanging baskets. Since Impatiens are sensitive to cold and slow-growing, starting seeds indoors well before spring is necessary. This head start ensures plants are mature enough for outdoor planting and provides a long season of blooms immediately following the last threat of frost.
Calculating the Optimal Indoor Start Time
The timing for sowing Impatiens seeds indoors is directly tied to your location’s final expected frost date. Seedlings require 8 to 10 weeks of indoor development before they can be safely transplanted outside. To determine the ideal starting date, first find your area’s average last spring frost date using local extension offices or online resources.
Once the last frost date is established, count backward 8 to 10 weeks to pinpoint the correct time to sow. Starting seeds too early can result in overcrowded, leggy, and weak plants that become root-bound. Starting them too late delays garden color, as plants take longer to reach flowering size outdoors. This approach ensures the seedlings are stocky and strong enough for the transition.
Step-by-Step Guide to Indoor Sowing
Sowing Impatiens seeds requires specific conditions for germination. Begin by preparing clean seed trays or individual cells using a sterile, fine-textured seed-starting mix to prevent fungal issues like damping-off disease. Moisten the mix thoroughly before sowing, allowing excess water to drain completely.
Impatiens seeds are light-dependent germinators and need light to sprout successfully. Press the tiny seeds gently onto the surface of the moist soil mix without covering them. Maintaining a consistent soil temperature of 70–75°F (21–24°C) is important. Covering the trays loosely with a plastic dome or plastic wrap helps maintain the necessary high humidity and warmth for reliable germination, which typically occurs within 7 to 21 days.
Essential Care for Growing Impatiens Seedlings
Once seedlings emerge, remove the plastic cover and move the young plants under a strong, supplemental light source. Providing 14 to 16 hours of light daily prevents stretching and “legginess.” Keep the light fixture 4 to 6 inches above the seedlings to maximize light intensity.
Proper watering involves keeping the soil consistently moist but never saturated, which can lead to root rot. Watering from the bottom by placing trays in a shallow pan allows the mix to wick up moisture, promoting stronger root development. After the seedlings develop their first set of true leaves, introduce a weak, water-soluble fertilizer diluted to one-quarter strength. Thinning the weakest seedlings at the soil line ensures adequate space for air circulation and growth.
Transitioning Seedlings Outdoors
Impatiens are sensitive to cold and should not be moved outside permanently until all danger of frost has passed. Nighttime temperatures must be consistently above 50°F (10°C) before transplanting. Seedlings must undergo “hardening off,” which acclimates them to harsher outdoor elements like wind, sun, and temperature fluctuations.
Begin hardening off by placing seedlings outdoors in a sheltered, shady spot for one to two hours daily, gradually increasing the duration over 7 to 10 days. This slow introduction prevents transplant shock, which can stunt growth or kill the young plants. The final planting location should be in partial to full shade, as Impatiens are prone to scorching and wilting in intense sun. Space the hardened-off plants 8 to 12 inches apart for proper air flow and development.