Common Name: Sunflower
Hardiness Zones: 2 to 11
Bloom Time: Most sunflower varieties bloom for several weeks in midsummer.
Plant seeds after the danger of spring frost has passed and the soil temperature is at least 60 degrees.
To plant sunflowers:
Space seeds about 6 inches apart in a shallow trench between 1 and 2 inches deep. ...
Cover and keep watered until seeds sprout in 7 to 10 days.
When first true leaves appear (the second set of leaves); thin plants to about 2 feet apart.
When the plant is small, water the area around the roots, about 4 inches from the plants.
It is recommended that you only soak most seeds for 12 to 24 hours and no more than 48 hours. ... After soaking your seeds, they can be planted as directed.