All You Need to Know About Growing Sunflowers

Choosing Seeds for Size

• If you plan to use sunflowers in a background planting and need a tall variety, consider "Sunzilla," a hybrid that grows up to 16 feet tall. For locations that require a 10- to 15-foot-high specimen, look at "Mammoth Russian" or "Paul Bunyan" varieties. "Tarahumara," which grows between 7 and 10 feet tall, and "Snack Seed," with a growth range of 6 to 8 feet, are other possibilities in the medium-size category. Reaching a height of only 2 feet, "Sunspot" produces many seeds and works in most landscapes.

Choosing Seeds for Color

• For color variety, consider "Fire in the Sky," which produces 12-inch, orange-red blooms on 10-foot-tall stems. Another color variation that produces a bushy plant with 4-inch flowers is "Bashful." Its pastel yellow-salmon-pink blossoms make excellent cut flowers because the blooms produce no pollen and last longer as a result. If you like the deep red color of Chianti wine and want to duplicate it in the garden, take a look at "Chianti Hybrid," which has wine-red petals flecked with gold. This hybrid sunflower has a bushy growth habit, reaches heights of 4 to 5 feet, spreads 18 to 22 inches and produces flowers 3 to 4 inches across.

Preparing the Soil

• If you have ever fed sunflower seeds to wild birds, you probably know how easy it is to grow sunflowers. As birds crack the shell, invariably some seeds fall to the ground. Without the help of human hands, these seeds sprout, providing a new crop of seeds for your avian friends. Sunflowers grow well in any garden soil, but they do not tolerate soil that remains waterlogged. Make sure you select a location that gets full sun. Sunflowers like soils with a pH of 6.0 to 7.5. Check with your local county extension agent to have the garden soil tested, and if necessary, adjust pH accordingly.

Planting the Seed

• Plant sunflower seeds in early spring after the last killing frost. Sow them 1 to 2 inches deep, leaving 6 inches between seeds and 18 to 24 inches between rows if you are planting in a garden setting. Cover the seeds with soil and water well. Seeds should sprout in seven to 10 days. Thin when the plants sprout a second set of leaves, leaving seedlings 2 feet apart. If your objective is maximum seed production, space the rows 2 to 3 feet apart. If you want smaller flowers for bouquets, space the plants closer together; 6 inches is a good choice, because it creates longer stems and smaller flower heads.

Growing Season Care

• Although sunflowers tolerate drought, water regularly if nature does not provide adequate rainfall. Regular, deep watering promotes a good root system, which is beneficial for the taller varieties. You may have to stake giant varieties, especially in windy areas of the country. If your soil is especially poor, consider top dressing with a granular, slow-acting fertilizer. A 2- to 3-inch layer of mulch helps cut down on moisture loss during hot summer days.

Harvest

• In early fall when sunflower heads turn toward the ground and the reverse side of the head turns yellow-brown, check the tiny petals cover the seeds. If the petals have dried and fall out easily when touched, the seeds are ready for harvest. Cut the seed heads off with pruning shears, leaving 1 foot of stem attached.

Curing

• Hang sunflower heads in a warm, dry, well-ventilated place that provides protection from wildlife, birds and bugs. This process takes from four to six weeks. When thoroughly dry, rub two heads together to unseat the seeds. You may also use your fingers or a stiff brush to remove the seeds from the head. Allow the harvested seeds seven to 10 more drying days, and then store them in an airtight glass jar. Storing the closed jar in the refrigerator helps the seeds retain their flavor longer.