Do Nighttime Sunflower Wilts Occur?

Sunflowers have circadian rhythms that regulate their growth, development, and responses to environmental cues. These rhythms arise in part because the abundance of growth-related factors such as light signaling components and hormones are regulated by both. At night, sunflowers close up their petals and turn their heads towards the west as a defense mechanism to protect their pollen from the cold night air. Sunflowers often wilt due to various reasons ranging from a lack of sunlight to pests and insufficient nutrition.

Contrary to popular belief, sunflowers do not actually close at night. Instead, they go into a state of rest called nyctinasty, where the flowers droop and the petals bend downwards. This helps protect the pollen from the cold night air.

If your sunflowers are drooping, there are several things you can do to help them. Sunflowers drink a lot and can dehydrate fast, causing them to wilt. Placing your sunflowers in a tall vase or pot might be all they need to add support to their long stems and stop them from drooping.

Sunflowers can quickly go from thriving to dying due to insufficient sunlight, poor drainage or improper pH in the soil, overwatering, lack of fertilization, or damage from pests. When sunflowers start wilting, they may look dry and ready for transplanting into the ground. Insufficient water can cause sunflowers to wilt and droop their heads, while temperature stress is common culprits.

Sunflowers do best when seeded directly outside, as they absorb groundwater during cooler night temperatures. It is important to ensure your sunflowers are not exposed to direct sunlight, cool drafts, or heat. Transplant shock may cause sunflower seedlings to bend, wilt, or slump earlier in the growing game.