How to Grow Sunflowers in Pots and How to Fix Yellowing Leaves

The sunflower is a relatively common plant in daily life, and its flowers have great ornamental value. Yellow ones are generally the most common, with a dark brown center where the seeds form. Many people like to grow sunflowers at home, but when growing them, problems can arise if you do not master the right techniques.

How to Grow Sunflowers in Pots

1. Temperature. Sunflowers are fairly adaptable to temperature and like a warm environment, but they can also tolerate low temperatures; as long as the temperature is not below 10°C, they can grow healthily. The most suitable temperature for growth is 18-30°C, with 10-18°C at night; keeping the day-night temperature difference at 8-10°C is good for the growth of stems and leaves. Within the suitable temperature range, the higher the temperature, the faster the plant grows; when the temperature is low, the plant grows slowly, which affects flowering. When the temperature is too high, above 25°C, pay attention to ventilation, and below 13°C, provide heating to keep it warm.

2. Light. Sunflowers are very sensitive to light and need plenty of it. Only with sufficient sunlight will the plant grow strong and the flowers be brightly colored and glossy. If there is a long spell of overcast and rainy weather, the leaves droop and turn yellow-green, and the flower heads vary in size.

3. Watering. Sunflowers have a well-developed root system and are drought-tolerant, yet also not drought-tolerant. From sowing to budding, a dry environment is good for the growth and development of the root system, but as light intensifies, water evaporates faster, and the plant needs nutrients to flower and set seed. Especially during the flowering season, replenishing water can ensure the quality of the flowers. Particularly when the pot is small and the plant is large, replenish water in time, following the principle of "alternating dry and wet."

4. Fertilizing. Sunflowers like fertilizer; during the growing period, apply fertilizer once every 7-10 days. During the seedling stage, sunflowers mainly need nitrogen fertilizer to promote strong branches and leaves. After budding, appropriately increase phosphorus and potassium fertilizer to promote flower bud development and benefit flowering. When the plant's branches and leaves are weak and the leaves are withered and yellow, replenish fertilizer in time, otherwise ornamental sunflowers lose their value.

What to Do When Potted Sunflower Leaves Turn Yellow

1. Water yellowing. If the new leaves of the sunflower plant are dull yellow and lack luster, the stems are thin and yellow-green, and growth is slow, but the old leaves show no obvious change, this indicates overwatering. At this point, control watering, take the plant out of the pot, let it dry in a cool place, and then replant it. When taking it out of the pot, be careful not to damage the soil ball around the roots.

2. Drought yellowing. If the plant turns yellow due to lack of water, the leaf tips and the base of the leaves dry up and wither first, and the plant turns yellow from the bottom up, but the new leaves grow normally. This is easy to solve; just water it. However, do not pour too much water at once; make sure to water thoroughly, and keep the soil moist.

3. Light-deficiency yellowing. Many plants get their leaves scorched by too much light. But sunflowers are different; they need plenty of sunlight during their growing period. If they are placed in a shaded environment for a long time, the leaves cannot see light, and the whole plant's leaves will turn yellow and fall off. Put the plant in the sunlight; if there is a lack of light, you can appropriately use a fluorescent lamp to supplement the light.

How to Manage Sunflowers

1. Seedling stage. The stage from emergence to budding is called the seedling stage. During this stage, the above-ground part of the sunflower grows relatively slowly, while the underground root system grows faster; this stage is when the sunflower has the strongest drought resistance. During this stage, water about once a week, fertilize once every half month, and ensure sufficient sunlight.

2. Budding stage. The budding stage is the most vigorous stage in the sunflower's life. During this period, sunflowers need the most fertilizer and water. If this stage cannot meet the sunflower's needs for water and fertilizer, it will seriously affect the sunflower's yield.

3. Flowering stage. The flowering stage refers to the period from the opening of the ray flowers of the flower head to the tubular flowers. At this stage, you should adjust the sowing time of the sunflowers, choose the right time to fertilize and water, prevent and control pests and diseases, and take measures such as releasing bees or artificial supplementary pollination, which can increase the seed-setting rate of sunflowers.

How to Prevent and Control Sunflower Sclerotinia Rot

1. Physical control: Once disease spots appear on the stems, leaves, or flower heads of the plant, pull out the entire plant to prevent the fungus from spreading. Sclerotia are very resilient and can survive in the soil for 3 years, so if there are other plants in the pot, it is recommended to change the soil and replant.

2. Chemical control: At budding and full bloom: spray a 1000-fold solution of Wenkulili, mainly spraying the lower part of the plant and the back of the flower head. At the seedling stage or flowering stage, spray a 500-fold solution of Sumilex, once every 5-10 days; the preventive effect is excellent. When the temperature reaches 18-20°C, it is the best time to apply chemicals to the soil surface. At this time, mix 70% quintozene with a small amount of moist soil and spread it on the soil surface, which can effectively inhibit the germination of sclerotia, with a preventive effect of 80%.

The method for growing sunflowers in pots is still quite simple. The above provides a detailed introduction, and everyone can learn more about it. If sunflowers develop yellow leaves, you can first understand the cause of the yellowing and then treat it. As long as management is strengthened in the later stages, sunflowers can still grow very well.