Sunflowers are common flowers that can be found in fields in rural areas. These phototropic plants have large, sun-like flowers that resemble human faces.


Sunflowers are considered cash crops because they can be cultivated for their edible seeds and oil, which have high economic value. Let's take a closer look at the characteristics of sunflowers.


Sunflowers are annual plants that only flower and fruit once a year. Edible sunflowers are usually single-flowered, with a main stem that is not branched, and the flowers are on the branches.


Sunflower flowers are very large, resembling a basin, and are yellow. One of the most distinctive features of sunflowers is that their flowers turn to face the sun.


Throughout the day, as the sun moves across the sky, the flowers follow its movement, always facing the sun. The plant gives off an exuberant energy, and its color gives a warm feeling.


Sunflowers are monopole-type plants that grow upright and unbranched. The height of the plant can range from 1 to 3.5 meters, and some ornamental sunflowers are short, branched, and full.


The edible sunflowers have separate stalks with broad, rough leaves and serrated leaf margins. The flowers of sunflowers range in diameter from 10 to 30 centimeters, and each inflorescence produces only one flower with a disk in the middle and petals on the periphery.


The fertility period of sunflowers refers to the number of days from seedling to seed maturity, which typically lasts between 85 to 120 days. However, the length of the fertility period varies depending on the variety, sowing period, and cultivation conditions.


From the emergence of seedlings to the emergence of buds, sunflowers enter the seedling stage, which generally lasts between 35 to 50 days, or 28 to 35 days during the summer sowing season.


This period is the stage of leaf and flower base formation and florets differentiation. The sunflower seedling stage is the most drought-resistant stage of the sunflower.


The above-ground growth is slow, but the lower-ground root system grows faster and forms a strong root system soon.


When the sunflower's present bud, a small, star-shaped body with a diameter of one centimeter, appears at the top of the plant, it takes approximately 20 days for the plant to flower.


This period is the most vigorous stage in the sunflower's life, as it requires the most fertilizer, and water, accounting for about 40 to 50% of the total fertilizer water needs. If the need for water and fertilizer is not timely met, it can seriously affect the yield.


During the sunflower field's flowering period, approximately 75% of the plant's ligular flowers are open, and it usually takes between six to nine days for the disk from the ligular flowers to open to the tubular flowers.


From the second to the fifth day, the inflorescence of the flowering period occurs, and the flowers mostly open at 4 to 6 am and are pollinated the following morning.


Unpollinated branches can remain unpollinated for 7 to 10 days. The sunflower's self-pollination fertility rate is very low, only about 3%, while the heterogeneous pollination fertility rate is high.


Finally, sunflowers require sunny weather, a large temperature difference between day and night, and suitable soil moisture for maturity. These conditions are crucial for the successful development of sunflowers.