With their bright yellow petals and big faces, sunflowers have served as a symbol of the sun for a very long time. Although sunflowers can withstand intense heat, they thrive in temperatures between 70 to 78 degrees Fahrenheit.
Sunflowers are heliotropes. That means they face east in the mornings, to the point where the sun will rise above the horizon. As it moves across the sky during the day, the sunflowers will follow its progress until they face west when the sun is setting. Overnight, sunflowers will gradually turn east again.
Even though heliotropism is less pronounced in mature sunflowers, the sun is very important to sunflowers.
Knowing how much sunlight sunflowers need can help you grow beautiful plants. To discover more, keep reading!
What Is Full Sun?
A location that is considered to be full sun receives 6 to 8 hours of direct sunshine on most days, typically between the hours of 10 a.m. and 4 p.m.
While many plants need full sun to develop properly, many of them cannot tolerate the extreme heat and dry conditions that often exist in these locations. That means a full-sun location in your garden can be tricky to manage.
Other factors include latitude and elevation. Gardens in southern regions receive more sunlight than gardens in northern regions, and the sun is stronger in high-altitude locations.
How Many Hours of Sun Does a Sunflower Need?
Sunflowers need at least 6 hours of direct sunlight a day. For sunflowers to develop to their full potential, with healthy, large blossoms, they need approximately 8 hours of sunshine. The more sunlight they receive, the better.
However, while sunflowers can tolerate hot, dry weather, if temperatures rise above 90 degrees Fahrenheit, they like some dappled afternoon shade.
Can It Grow in Indirect Light?
Sunflowers can tolerate partial shade, but there are some drawbacks. While the stems and leaves will develop just fine in indirect light, the blossoms will develop more slowly and it won’t be as spectacular as when the plant grows in full sun.
Can It Grow in Shade?
Sunflowers can tolerate some shade, but you will be able to tell that they lack the sunlight they prefer. The plants will grow tall and leggy and produce fewer blossoms.
Your sunflowers’ lengthy tap roots suffer from a lack of sunshine as well. Shady locations usually have soil that is likely to remain damp for long periods of time. This is often the cause of root rot. Once the tap roots are infected with root rot, the disease will quickly spread to the rest of the plant. It will eventually get stressed or die as a result.
Can Sunflowers Get Too Much Sun?
Sunflowers like to soak up as much sun as possible. There is no such thing as too much sun when it comes to these plants. However, you do need to keep an eye on the temperature. Sunflowers can easily handle temperatures as high as 90 degrees Fahrenheit. If it gets hotter than that, though, the plants will likely begin to wilt. If you are experiencing a heat wave where you live, use a green shading net or something similar to keep your sunflowers from getting burned by the sun.
