Sunflowers grow best in environments where temperatures range between 70 and 78 degrees Fahrenheit, but they can grow in temperatures ranging from 64 to 91 degrees Fahrenheit. Sunflowers are able to germinate at temperatures as low as 39 F, but growing seedlings can perish at temperatures below 28 F. Sunflowers love sunlight and grow best when exposed to direct sunlight for at least six to eight hours a day.
Sunflowers flourish in environments where long hot summers are the norm. They grow in a variety of soil types, but the soil must have good water drainage. These flowers have long roots that need lots of space to grow, and flower beds must be dug at least 2 feet deep and 3 feet across. Plant sunflower seeds in loose soil that has a pH level between 6.0 and 7.5. While sunflowers are relatively easy to grow, they do require lots of nutrients, which they receive from compost or organic matter. Take care not to over fertilize them, because overfeeding causes plant stems to break.
Sunflowers usually bloom in the summer and can grow up to a height of 16 feet. Most insects don't bother this bright yellow flower, but some birds and squirrels eat raw sunflower seeds, and the flowers do attract bees. Smaller sunflower plant varieties are ideal for gardens with limited space.