Planting Temperatures for Wild Sunflowers

Characteristics

• In appropriate growing conditions, wild sunflowers grow up to 3 feet in height. The petals are vivid yellow. Wild sunflower is an annual and will die at the first frost of fall. It's possible for the flowers to regrow from seeds, but only if they fall onto bare ground and manage to take root. The flowers will bloom in midsummer if the seeds are planted in warm soil that's reached a safe temperature.

Climate

• Wild sunflowers are native to the United States and grow in U.S. Department of Agriculture hardiness zones 3 through 10. Wild sunflower is tolerant of many different soil types, but the flower must be planted in a site where it will receive full sunlight. The soil should be well drained; wild sunflower will not grow in waterlogged or excessively moist conditions. Before planting wild sunflowers outdoors, gardeners are obliged to wait for the soil to reach the right temperature.

Temperatures

• Wild sunflower is intolerant of frost, and even a light freeze may cause damage. Light freezes occur when outdoor temperatures reach between 29 and 32 degrees Fahrenheit. Moderate freezes will certainly harm sunflowers, the tender youth growth and mature plants. A moderate freeze occurs when temperatures fall from 25 to 28 F. When temperatures fall below 24 F, the damage to wild sunflowers may be fatal. Wild sunflowers may not be planted until danger of frost has passed. Wait for the soil to become warm and workable before sowing seeds outdoors.

Planting

• Plant wild sunflowers in full sunlight. Even a little shade may harm the flowers. Sunflowers are named not just for their vivid petals, but for their sun-loving nature. The blossoms point toward the sun and will fall over onto the ground if they are placed in a shady site. Wild sunflowers are short-lived, and may live for only 60 days. Sunflower seeds may be planted outdoors as soon as danger of frost has passed, but you may also grow them indoors and transplant seedlings once temperatures are warm enough.