The sunflower (Helianthus annuus L.) is known for the heights to which it can grow and for the very large round yellow flowers that bloom in late summer to early fall. Gardeners often grow sunflowers just for the challenge of creating the height that makes the plant so unique. The growth of a sunflower is surprisingly not complex, but requires an understanding of the important fundamentals that make a sunflower grow. In addition, sunflowers are grown commercially for different uses.
A sunflower is actually hundreds of tiny flowers clustered together. The disk flowers form in the center, It takes approximately five to 10 days from planting to emergence and 33 days for the head to be seen.
Differences in maturity are due to the conditions in the period before the head is visible. Sunflowers grow best in temperatures of 70 to 78 degrees Fahrenheit. They are not considered drought tolerant and require good drainage.
Planting from Seeds
Several varieties of sunflowers are available. Most types of seeds are hybrids and it's recommended to buy new ones every year. Plant sunflowers 1 to 1 1/2 inches deep. Good spacing depends on the size of the seed.
Planting time depends on the weather. In climates without harsh winter weather, sunflowers can be planted anytime. In places with harsh winters, do not plant the seeds until the soil has warmed up to 50 degrees. Planting too late can cause damage to the heads by insect larvae. Planting in May is recommended in Minnesota and Wisconsin.
The key with sunflowers is to make sure they are not over-watered for an extended period of time, Wet soil can loosen causing unstable conditions to support the weight of the flower, especially in the wind. A group planting is beneficial as it helps maintain moisture in the soil and being close to one another can block the plants from wind damage. Depending on the soil, they may need some nitrogen, or if the soil is sandy, extra potassium can help.
Due to the height of sunflowers, tilting over is always a concern. Once they are large enough, they can be staked. This is most effective in smaller plant groupings.
Uses for Growing Sunflowers
Sunflowers grown in smaller gardens can be grown for different reasons. One is for cut flowers. They can also be grown as food for humans or animals. Birds eat the seeds if the heads are not properly protected,
Many people eat sunflower seeds as well. They are sold commercially either still in the seed hull or as a raw seed. Commercial growers raise approximately three million acres of sunflowers each year in the United States for sunflower oil.
Sunflowers are a food crop of worldwide importance, Sunflowers date back at least 1,000 years and are native to North America when they were cultivated by Native Americans. Modern sunflowers were not grown much in the United States until the 1970s.