Sunflower Plant Growth

The time it takes for a sunflower plant to grow to maturity depends on the type of sunflower planted and the growing conditions.

Emergence

Sunflowers generally take about 11 days to poke out from the soil after planting.

Vegetative Stages

The vegetative stages come after emergence. An agronomist determines what vegetative stage a sunflower is in by counting the number of true leaves that are at least 1.6 inches long on the plant. A plant could easily reach up to vegetative stage 12 before beginning reproduction.

Reproductive Stages

Reproduction begins when the terminal bud forms. A floral head emerges, grows and blooms. The main sunflower head is composed of 1,000 to 2,000 individual flowers joined to the same receptacle. After flowering, any smaller flower heads on the plant begin to wilt and the back of the main flower's head turns yellow.

Maturity

The sunflower's bracts, the pointy parts on the back of a flower head, become yellowish brown when the plant is fully mature.

Harvest

Once the sunflowers are mature, they are often left in the field or garden to dry until the seeds are below 10 percent moisture, which is recommended for long-term storage.

References

• Purdue Horticulture
• North Dakota State University