Impatiens, often called the “Busy Lizzie,” is a popular annual plant prized for providing vibrant color in shady garden spaces. Starting these plants from seed is a cost-effective way to fill containers and flowerbeds. Germination is the initial stage of growth where the dormant seed sprouts a radical and shoots. Understanding the specific environmental needs for this phase is key to successfully growing these flowers.
The Typical Germination Timeline
Under consistently ideal conditions, Impatiens walleriana seeds typically complete their germination process within a window of 10 to 20 days. This timeline is contingent upon maintaining a precise balance of temperature and moisture around the seed. Some growers report seeing the first sign of life within a week if conditions are perfect.
The successful conclusion of this period is marked by the emergence of the cotyledons, which are the plant’s first embryonic leaves. These initial leaves appear rounded and are distinct from the true leaves that will develop later. If the seeds are sown in a warm, controlled environment, most of the sprouting activity should be complete within the first two weeks.
Essential Environmental Requirements
Achieving the shorter end of the germination timeline depends heavily on providing a specific and stable temperature range. Impatiens seeds require a warm soil temperature, ideally maintained between 70°F and 75°F (21°C to 24°C). Utilizing a thermostatically controlled heat mat is the most reliable method for ensuring the growing medium stays consistently within this optimal range, as room temperature alone is often insufficient.
Proper planting depth and light exposure are also factors for Impatiens seed. The seeds should be surface-sown and gently pressed onto the soil, but not covered with the growing medium. Impatiens are light-dependent germinators, meaning exposure to light is necessary to break dormancy and initiate sprouting.
The growing medium must be kept uniformly moist throughout the entire germination period to soften the seed coat and activate the embryo. To maintain high humidity and prevent the surface-sown seeds from drying out, covering the planting tray with a clear plastic dome or plastic wrap is recommended. Avoid placing this covered tray in direct sunlight, as high temperatures can inhibit germination completely.
Common Reasons for Delayed or Failed Germination
The most frequent cause for a delayed or failed germination is a soil temperature that is too cool or inconsistent. When the temperature of the seed starting mix drops below the required 70°F threshold, the seeds often enter a state of dormancy or simply take much longer than the expected two weeks to sprout. A fluctuating temperature, such as the drop that occurs overnight, can be just as detrimental as a continuously cool environment.
Improper watering practices represent another major hurdle for the delicate seeds. Overwatering creates a soggy, oxygen-deprived environment that encourages a fungal disease known as “damping off,” which causes the emerging seedlings to collapse and die at the soil line. Conversely, allowing the surface of the soil to dry out completely, even briefly, can quickly dehydrate and kill the newly activated seeds.
Planting the seeds too deep is a common error that prevents successful sprouting. Because the seeds require light to germinate, burying them under a layer of soil will block the necessary signal. Finally, the age of the seed stock impacts success, as old or improperly stored seeds may have a reduced viability rate, leading to poor germination.