Key Points for Sowing and Field Management in Sunflower Cultivation

The sunflower is an annual herbaceous plant of the genus Helianthus in the aster family (Asteraceae). Its seeds can be pressed for oil or roasted for eating, and its large, striking flowers are often grown for ornament; it is also a good nectar plant. It prefers warmth and plenty of sunlight, and in the early stage of growth its flower disc turns to follow the sun, which is how it got its name. Sunflowers have a well-developed root system and fairly strong drought tolerance, and they are not demanding about soil, though they grow better in loose, fertile, well-drained plots.

Sunflowers are generally sown in spring once the ground temperature has steadily risen, or a summer sowing can be arranged depending on the intended use. Before sowing, plow the soil deeply and apply plenty of base fertilizer; the seeds can be soaked and pre-germinated as appropriate, then sown in hills at a reasonable spacing between plants and rows. Keep the soil moist after sowing, and seedlings will emerge before long. After emergence, thin and then set the seedlings in good time so that the young plants are not crowded, which would hinder their growth.

Management during the growing period centers on water and fertilizer. Around budding and flowering is the key stage for water and nutrient needs; fertilizer based mainly on phosphorus and potassium can be applied along with watering to promote flower disc development and full seeds. In windy areas, tall varieties can be earthed up or given supports to prevent lodging, and attention should be paid to controlling diseases and pests such as sclerotinia, rust and aphids, while weeds in the field are removed promptly.

The crop can be harvested when the back of the flower head turns yellowish brown and the seeds harden; harvesting too late makes the seeds liable to shatter or be pecked by birds. For ornamental growing, dwarf, many-flowered varieties can be chosen for pot culture and placed in a sunny spot, with much the same management. Overall, sunflowers are highly adaptable and not difficult to grow, and with proper management they can give a good harvest or a fine ornamental display.