Sunflower is an annual herbaceous plant, and its flowering period varies with different varieties.But it usually blooms in summer and autumn, belonging to summer flowers.If it is sown in March and April, its flowering period is in July and August, and its maturity period is in August and September.There are two kinds of flowers on the disk: ligulate flowers and tubular flowers.Ligulate flower 1-3 layer, insert the all round brim that gives birth to dish, for asexual flower.Tubular flowers are located on the inner side of ligulate flowers and are bisexual flowers.The size and color of flower discs vary with varieties, generally orange, light yellow and purplish red.
1. Planting time: Sunflowers are best planted in March and April.At this time, the temperature and humidity are suitable for planting, and the survival rate will be higher.
2. Planting land selection: Planting land can be selected in the place where the land is flat, medium fertility, convenient irrigation and low soil viscosity.
3. Temperature: the suitable temperature for sowing is between 18 and 25 deg C.Usually when the temperature rises to 20 degrees, the seeds will begin to germinate in about 5-7 days.When the local temperature is stable above 2 C, the seeds begin to germinate, and when the temperature is 4-5 C, they can germinate and take root.When the ground temperature reaches 8-10 deg C, the seeds can germinate and emerge.Sunflower can grow normally as long as the temperature is not less than 10 C during the whole growth process.
4. Water and fertilizer: different growth stages of water and fertilizer requirements will be different.Between the seedling stage and the budding stage, the demand for water and fertilizer is low.The demand for water and fertilizer at budding stage and flowering stage will increase significantly, and the demand for water and fertilizer will be met in time, otherwise the yield will be seriously affected.The demand for water and fertilizer at maturity is also high, but not as high as before, so it is necessary to reduce the amount of water and fertilizer appropriately.
5. Illumination: It needs plenty of sunlight, and its seedlings, leaves and flower discs have strong phototropism.Sufficient sunshine can prevent excessive growth, promote vigorous growth of stems and leaves, and improve seed setting rate.
