Growing Sunflowers 101

The Growing Site

• Select a site to plant sunflowers that receives 6 hours or more of direct sunlight per day. Cultivate the soil to a depth of 12 inches, making sure to incorporate plenty of organic matter into the soil. Add sand or peat moss to heavily compacted soil. Sunflowers prefer growing in loose, moist, well-drained soil.

Sowing Sunflower Seeds

• Start sunflower seeds indoors in peat pots four weeks before the last spring frost. Sunflower seeds take up to 14 days to germinate. As soon as you see signs of growth, begin exposing the seedling to the outdoors. Begin by setting it outside in a shady area for about an hour and slowly increase the plant's exposure until the seedling remains outside in full sun the entire day. This process is called hardening off. Direct sow seeds outdoors in the garden as soon as the soil temperature is above 50 degrees Fahrenheit. Use a soil thermometer inserted into the ground for five minutes to determine the soil temperature. Seeds that are direct sown do not need hardening off. Start them approximately four weeks before the last spring frost. The seedlings that emerge are able to tolerate light frost.

Transplanting and Caring for Sunflower Plants

• Once the last frost is over, transplant the hardened-off seedlings into the garden. Do not remove them from their peat pot because sunflowers do not transplant well. The peat pot is made to biodegrade once it is in the ground. Thin the young sunflowers that were direct sown, if necessary, so they have adequate room to grow. Place stakes next to the stems of tall sunflowers so you can begin staking them once they are 2 to 3 feet tall. High winds or heavy seed heads often cause sunflowers to fall to the ground; the stakes help prevent this from happening. Mulch the soil around the sunflowers once they are established. Water at least once a week if there is not adequate rainfall. Sunflowers are heavy feeders that benefit from regular fertilization with a balanced fertilizer such as 10-10-10. Apply the fertilizer according to the package label.

Saving Sunflower Seeds

• Once a sunflower is past its prime, seeds begin to form in the center of the flower. Birds love to eat these seeds, especially finches, and they are also a nutritious snack for people. To prevent the birds from devouring all the seeds, cover the seed heads with pantyhose. Make sure to do this while the seeds are still green. Once the seed head begins to turn brown, cut it off at the stem. The back of the seed head may still look lemon-green, but this is fine. Hang the seed heads in a cool, dark and dry place. Allow the seeds to fall out into the pantyhose. Once you feel enough seeds have fallen, remove the pantyhose from the seed head and gently rub the seed head to release any remaining seeds. Dry the seeds for two weeks if you intend to store them to re-plant. If you want to eat them, roast them until they are golden brown, allow them to cool, then place them in a sealed jar to eat when desired.