Can sunflower seedlings be basked in the sun?
As the most confusing problem for novice gardeners, the maintenance of sunflower seedlings requires mastering scientific methods. This vigorous plant requires both sufficient light and special care during the seedling period. How to avoid burns while ensuring photosynthesis has become the key to cultivating healthy plants. This article will systematically analyze core points such as lighting management and environmental control. Sunflower seedling light management principles Morning light maintenance principles During the seedling period, the rule of "3 hours in the morning" is followed, and the period from 6 to 9 a.m. is selected for light. At this time, the ultraviolet intensity is about 1.5-3.0μW/cm², which can not only promote chlorophyll synthesis, but also avoid leaf burns caused by strong noon light (>8μW/cm²). It is recommended to use a sunshade net to filter 30% of the light and immediately transfer it to a scattered light environment when the temperature exceeds 28 ° C. Light adaptation training The light duration will be gradually increased from the second week of emergence, extending it for 30 minutes every week until it adapts to full sunshine. The adaptability is judged by the change in blade thickness-the thickness of healthy blades should reach 0.2-0.3mm, and if thinning occurs, it needs to be adjusted immediately. Intelligent moisture control of sunflowers 'healthy growth factors adopts the "knuckle detection method": insert your index finger into the second knuckle of the soil, feel the humidity and decide to water. The ideal substrate moisture content should be maintained at 45-55%, watering 200ml/plant every 72 hours in spring and autumn, and adjusted to a 48-hour cycle in summer. It is recommended to use red pottery pots to enhance breathability and avoid the risk of water accumulation in plastic pots. Precise temperature control builds a miniature greenhouse to maintain a golden temperature of 18±2℃, and uses a double-layer sunshade net to build a day and night temperature difference system: the outer net is lifted during the day to warm up, and it is covered at night to maintain heat. Heating cables can be laid during the cold current to keep the root temperature no lower than 15 ° C. Nutritional science rations use nutrient solutions with EC values of 1.2-1.5mS/cm at seedling stages, and adjust the ratio of nitrogen, phosphorus and potassium to 3:1:2. 30 days after planting, decomposed earthworm manure (50g per pot) can be applied, combined with alginate foliar fertilizer (diluted 2000 times) to enhance stress resistance. Pay attention to avoid quick-acting fertilizers such as urea to prevent root burning.
Through phased light adaptation, precise environmental control and scientific nutritional management, sunflower seedlings can quickly establish strong root systems. Keeping in mind the concept of "progressive maintenance" and combined with regular observation (measuring plant height growth of 1- 2 cm per week is normal), high-quality plants with flower diameters of up to 8cm can be cultivated. It is recommended to establish a maintenance log to record daily temperature and humidity changes and growth response.