Sunflower Growth Stages

Knowing the life cycle of a sunflower will help you become a better gardener. How does it grow?

Growing a sunflower is not difficult, but understanding its growing stages will help you notice issues as they occur.

The key stages of the flower life cycle are seed, germination, vegetative growth, bud formation, flowering, and seed collection.


The seed represents the plant’s dormant, underdeveloped stage. This is the beginning of the life cycle.

The sunflower seed, with its shell still attached, is a single dried-out fruit of a plant. This whole seed has all of the nutrients and genetic information needed to grow a new sunflower plant.

Its seed is a dicot since the plant belongs to the Asteraceae family, which contains two cotyledons in its seeds.

The size of the seeds varies, but they are usually approximately 7 mm in length. Plant the seeds 1 to 1.5 inches deep in the soil.


To germinate, the seed must be sown in the appropriate location at the right time. Germination might take up to eight days under optimal temperature and moisture conditions.

After a few days in the soil, the seed absorbs water and expands to the point where the seed coat splits. The wispy roots extend out, and a growing sprout makes its way to the top of the dirt in pursuit of sunshine.

The cotyledons will fall off shortly after that, and the first true leaves will emerge. 

Sunflower germination at home using wet gauze and recycled containers

Vegetative Growth

Our seedling has become a little sunflower plant. This is its growth stage, and it is aiming to expand as much as possible.

A freshly sprouted sunflower usually has two infant leaves, but many more arise as the stem gets taller. The first few sets of sunflower leaves are typically oval in form, but as additional leaves appear, they resemble the heart-shaped leaves of a mature sunflower, although on a smaller scale.

In order to finish the floral life cycle stage of development, plants must generate their own energy. This is referred to as photosynthesis. The photosynthetic process starts as soon as the leaves sprout.

The root system continues to grow, anchoring the plant to the ground and creating root hairs that help absorb water and nutrients.

The stem grows in length toward the sun and transports water and nourishment between the roots and leaves. Sugars and starches are transformed into the energy required to generate new plant growth.

This stage lasts 45 to 60 days, or until flower structures emerge.

Just sunflower leaves growing in the garden

Bud Formation

You will see the creation of a bud after the vegetative growth stage. The bud may initially seem star-like, but it will have evolved into the long-stemmed, yellow-blooming plant by the end of this phase.

This stage lasts around 30 days.

A sunflower bud forming after vegetation


After your sunflower has completely flowered, you’ll have around 20 days to enjoy its splendor. Bees may pollinate and fertilize the seeds during the blossoming period.

The best time to admire your sunflower’s golden blossoms is during flowering. Put your flowers in a vase, make a bouquet, or make an autumn wreath.

A blooming sunflower under the heat of the sun


Pollinators are required by sunflowers to carry pollen from one flower to the next. Wind pollination is insignificant as opposed to other crops like corn. Sunflower pollen is heavy and sticky, and on windy days, the majority of it settles on the plant’s leaves.

Flowers pollinate themselves from the outside in, and once pollinated, the seeds underneath change from white to black. When a plant is stressed, the flowers usually do not pollinate completely.

Drying and Seed Collection

When the sunflower plants attain physiological maturity, they are left to dry out in the field for up to two months.

Harvesting sunflower seed heads before the plants have dried out makes the process more difficult. Excess moisture causes seeds to adhere to the fleshy part of the seed head, resulting in a decreased yield.

After gathering the seeds, they may be planted, and the complete life cycle can begin again.

Carley Miller
Carley Miller is a horticultural expert at Bustling Nest. She previously owned a landscaping business for 25 years and worked at a local garden center for 10 years.
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