Impatiens are an abundantly blooming summer annual. Double impatiens have two sets of petals on each flower, giving them a fullness similar to that of a rose. They come in shades of pink, lavender and white. Some varieties have two colors on each flower that add more interest to the garden. Shade tolerant, they add color to parts of the garden where other annuals won't bloom. Sowing double impatiens seed is no different than sowing regular impatiens, but you get more striking flowers for use in beds and containers.
Start impatiens seed eight weeks before the last expected spring frost in your area. Fill seed starting trays with a soil-less potting mix prior to planting.
Moisten the soil until it is evenly moist but not soggy. Sprinkle the seeds on the soil surface in rows and lightly press on them so they have full contact with the soil. Double impatiens seed is very small, so sow as thinly as you can.
Cover flats with a layer of plastic wrap, then place them in a 70- to 75-degree F room near a sunny window or under grow lights placed 4 inches above the flat, as double impatiens require light to germinate. Germination occurs within seven to 10 days after sowing.
Remove plastic once seeds germinate. Water flats from the bottom to keep soil moist but not wet and leave under grow lights for 12 hours a day, or place in a sunny window for six hours a day.
Transplant seedlings to individual pots once they develop their second set of leaves. Fill pots with potting mix and moisten. Lift each healthy seedlings from the flat by the top leaves and plant into the new pot.
Fertilize every two weeks with a half-strength liquid feed. Transplant to the garden once all danger of frost has passed in your area.