What is the environmental conditions that the sunflower needs?

Sunflowers need full sun. Average, moist garden soil that has been tilled or softened to a depth of around a foot or so. When watering, water deeply in the morning hours to prevent powdery mildew for forming on the leaves. Water at the base of the stem and try to keep the leaves dry (avoid overhead sprinklers).

Sunflowers my need staking in windy areas or when growing the tall Russian mammoth varieties. Once the flower is through and the petals are withered (unless you are growing the plant to harvest it's seeds), the plant can be removed and replaced with an additional sunflower to keep the blooms coming throughout the season (just give the replacement plant periodic fish emulsion feedings to replace some of the nutrients back into the soil).

There are many varieties of Sunflowers. Some are very large and tall, some are dwarf and there are branching varieties. Ranging in colors from white, cream, maroon and the traditional golden color. Most are planted as annuals but there are some perennial versions that bloom for portions of the summer.