Plant your impatiens seeds in a purchased seeding container, clean pre-used food container or paper cups. Any of these will work fine. Start by filling the containers with commercial potting soil to ½ inch from the top of the rim.
Spray the soil with a water bottle mister to moisten. Stir the soil around so the water is mixed in.
Sprinkle a three to five seeds on top of the soil in each container. Very small seeds, such as impatiens, do not need to be placed in a hole in the soil. Press down on the seeds with your fingers, so the seeds make contact with the soil and will stay in place.
Place your containers in a tray. Cover the tray with a sheet of plastic wrap. This will help keep the soil warm so that the seeds will germinate (pop out of the seed shell and sprout).
Place the tray near a window. Impatiens are best when receiving only partial sun. Don't place them too close to the window, but close enough so they will get indirect sunlight. The room should be kept fairly warm, 70 to 75 degrees Fahrenheit. Remember, you are trying to trick the seeds into thinking it is a warm springtime period.
Remove the plastic wrap when the impatiens seeds have germinated, in about ten days.
Water the soil when it starts to dry with your water bottle mister. It's important that the new seedlings receive enough water. However, too much water can cause dampening (fungal disease). Be cautious not to over water.
Fertilize your impatiens seedlings once a week when they have grown two sets of leaves. Mix house plant fertilizer with water to make it half-strength.
Harden off your seedlings when they are 2 to 3 inches tall and have at least two sets of leaves. This should be done after the last frost in your location. The term, harden off, means to acclimate the tender seedlings to outdoor conditions. Start by placing them in a sheltered location outdoors for a few hours and then bring them back inside. Increase the time each day, for the next few days, while moving them into less protected areas.
Transplant your impatiens into their final home, either in the ground or in outdoor containers.