Common Sunflower

Annual plant of the Compositae family with an erect stem 2-3 m tall. Flowers in heads of bright colors from yellow to red. Mild to warm climate. The planting season for rainfed crops varies according to latitude, but lasts approximately one month from the beginning of summer. Planting should be done in rows 0.70 m apart, with a planting density of four plants per linear meter. It is an undemanding crop regarding the type of soil, although it prefers clay-sandy soils rich in organic matter, but it is essential that the soil have good drainage and the water table is at a shallow depth. The germination of sunflower seeds depends on the temperature and humidity of the soil, with the average temperature being 5 °C for 24 hours. The planting depth is carried out according to the temperature, humidity and type of soil. In humid areas with warm springs, with heavy and humid soils, the sowing depth is 5 to 6 cm. In areas with dry springs, with light soils and low humidity, the sowing depth is 7 to 9 cm. If the soil is light and soft, the planting depth is greater, contrary to what happens if the soil is heavy. The plants that come from shallow sowings germinate and flower before those from deep sowings. Some varieties developed recently have decayed heads. These varieties are less attractive to gardeners who keep the flowers as ornamentals, but attractive to farmers because they can reduce bird damage and losses from plant diseases.