Impatiens are most often purchased as seedlings and planted annually. But these plants are also easy to propagate from seed. And many gardeners opt to plant the seeds from last year's purchased seedlings to save the expense and the trip to the nursery. For the best results, however, you'll still want to follow the nursery's lead and refrain from planting your impatiens seeds directly into the ground. Instead, start these minuscule seeds in seed flats in February and transplant them outdoors in spring once they begin to mature.
Wash your planting tray with soap and water and rinse it well. If the planting tray has been used before, dip it in a solution of one part bleach, nine parts water to sterilize it.
Fill the planting tray to within 1/2 inch of its lip with a quality seed-starting potting soil. Then pat the soil down gently with your hands to firm it.
Water the soil by partially submerging the tray in water until the soil draws up enough water to moisten its surface. Pull the container out of the water and allow it to drain for an hour or so.
Pour your impatiens seeds into a small dish. Moisten the end of the toothpick with your tongue and touch it to a single seed. The seed should stick to the moist end of the toothpick.
Press one seed into the center of each cell. Then cover the seeds by sprinkling them with potting soil.
Moisten the soil following the method in Step 3.
Place the clear plastic lid over the seeding tray and place it in a spot that is room temperature and in indirect sunlight. Remoisten the soil if it dries out (following the method in Step 3) until the seeds germinate in one to two weeks.