Can Sunflower Plants Be Started Indoors?

Why Start Indoors?

• Gardeners start seeds indoors for a variety of reasons. One reason is that many tender seeds would not be able to tolerate the last cold days of spring. Seeds that require such treatment are usually started indoors about four to six weeks before the average last frost date. In addition, some seeds are simply too small to toss into the garden where they'd get lost, and it's much more efficient to grow transplants indoors.

Hardy Annuals

• Sunflowers are hardy annuals and their seeds are rather large -- about 1/8 inch long -- and easy to handle. Their hardiness means they can tolerate a light frost or two if they sprout before the average last frost date. Sunflowers sprout fairly quickly, within a week or two, making it impractical to carefully tend to their seedlings indoors when they will do just as well, if not better, in the garden. The seedlings are also susceptible to transplant shock and dislike having their roots disturbed.

Sunflower Seed Requirements

• Sunflowers require a site in full sun with virtually any type of soil; they'll thrive in pretty much anything, making them one of the best flowers for poorer soils. Most sunflowers are quite drought tolerant, as they are native to the prairie, but deep watering encourages the sunflowers to develop strong root systems, providing the necessary support for those flowers that are destined to be tall with large heads.

Planting Sunflowers Outdoors

• Choose a site in full sun with average soil. Dig shallow trenches, about six inches apart, or scatter seeds in a soft bed and cover them with about an inch of soil. Water the seeds and the seedlings until they have their first set of true leaves. Thin the seedlings to two feet apart when they've sprouted and plant new seeds every two to three weeks to ensure continuous blooms until the fall.