How to plant Japanese bluebell seeds: Steps for planting Japanese bluebell seedlings

How to plant Platycodon grandiflorusA comprehensive introduction to how to plant Platycodon grandiflorus and the steps for planting Platycodon grandiflorus seeds in the field of green plants and flowers, specifically as follows:Platycodon grandiflorus has a rich variety of colors, including purple, rose red, pink, silver white, and various other bicolors. The flower shape is divided into single and double petals, mainly used for cut flower production, can be potted, and can also be used to decorate flower beds. Currently, Platycodon grandiflorus is widely cultivated around the world and is increasingly popular, with flower shops and windowsills in European countries everywhere, making it one of the fastest-growing cut flower species in the world.In the northern regions of China, the climate is cold, the frost-free period is short, the cost of cut flower production is high, and the development of the cut flower market is extremely slow. Fresh cut flowers consumed are mostly dependent on the southern provinces or imports, resulting in poor freshness and low ornamental value, which has affected the development of fresh cut flower consumption. The most suitable temperature for the seedling stage of Platycodon grandiflorus is 20°C. If the temperature exceeds 28°C continuously for more than 2 weeks during the seedling stage, it is prone to produce dwarfed rosettes, resulting in the difficulty of internode elongation. The flowering stage requires sufficient light, high temperature, and less rain, making it very suitable for cultivation in the north.Platycodon grandiflorus can be produced in the open field or in protected cultivation in artificial greenhouses or greenhouses.1. Sowing Techniques(1) Seed Treatment TechniquePlatycodon grandiflorus seeds are small, and the seeds should be soaked in water before sowing to remove the floating immature seeds from the surface. Soaking for 48 hours can improve germination rate and shorten germination time. After soaking, remove the seeds and slightly dry the surface moisture before sowing.(2) Seedling Nutrition Soil PreparationPlatycodon grandiflorus is commonly propagated by sowing, which can be done in indoor pots or directly in the open field. The sowing soil should be disinfected before use, and can be treated with 0.3% formalin or potassium permanganate. The ratio of the components in the seedling nutrition soil is garden soil : peat soil : sand : rice husk (or perlite) = 3:4:2:1, filled into the seedling trays, flattened with a pressing plate, and soaked with water to ensure the soil is fully absorbent and the surface is level.(3) Sowing MethodWhen sowing, mix fine sand with seeds through a 0.1mm sieve, with a ratio of about 100:1 sand to seeds. Thoroughly mix and evenly sprinkle on the seedling trays, with about 8000 seeds per square meter. Do not cover the seeds with soil after sowing. Finally, cover the seedling trays with plastic film and flip them twice a day to shake off the evaporated water vapor. Keep the soil moist during the germination period.(4) Sowing TimeThe best sowing time for Platycodon grandiflorus is between November and December. Different sowing months result in significant differences in the number of days from sowing to flowering. For the same variety, sowing in spring requires only 4 months to flower, while sowing from July to September takes 8 to 10 months to flower.There is also a big difference between varieties, with early-maturing varieties flowering in 100 to 120 days after spring sowing, while late-maturing varieties take 150 to 180 days. Generally, the longer the cultivation time, the higher the quality of the cut flowers. Therefore, it is very important to adjust the harvest period based on the different production cycles of the varieties.(5) Management Before Germination30°C is the optimal temperature for the germination of Platycodon grandiflorus seeds. After sowing, maintain the temperature or use artificial heating to ensure timely germination of the seeds, and use black film or non-woven fabric for shading treatment.2. Seedling Stage ManagementPlatycodon grandiflorus seedlings grow slowly and require careful management during the seedling stage. Calculate the sowing amount to prevent excessive density, and try not to damage the roots during thinning. When the seedlings have grown 4 true leaves, they can be transplanted into pots of 8cm to 15cm in diameter, greenhouse production beds, or open field. When transplanting, also be careful not to damage the roots, otherwise, the seedlings will struggle to recover normal growth.The soil for transplanting should be finely cultivated, level, and have good drainage, with a pH value between 6.3 and 7.0 for slightly acidic soil. Platycodon grandiflorus prefers soil rich in calcium and with an appropriate amount of phosphorus, so the soil acidity should be adjusted and calcium and phosphorus fertilizers should be applied as base fertilizers before planting. If possible, the soil should be deeply turned once a year to ensure loose soil without compacted layers. Platycodon grandiflorus is very sensitive to soil-borne diseases, and the soil must be disinfected for consecutive cropping.Soil that is too acidic can lead to symptoms such as yellowing of tissues, browning of leaf tips and stems, and poor root development.How to plant Platycodon grandiflorusThe impact of environmental conditions during the seedling stage affects the growth and development of seedlings after transplanting, so attention should be paid to temperature, day length, and fertilization and water management. The growth rate of Platycodon grandiflorus seedlings is slow and varies greatly with the sowing season. It takes about 2 months from sowing to the development of 4 leaves, which requires strict temperature control. When the day and night temperatures exceed 26°C or fall below 10°C, the leaf rosette forms, the stems do not elongate, and no flowers are produced. Therefore, after germination, the seedlings should grow at a temperature of 22°C to 25°C during the day, and the night temperature should be reduced to 13°C to 15°C, allowing for a relatively low-temperature process and a certain temperature difference to pass through the vernalization stage. Since flower buds differentiate at low node positions under high temperature and long-day conditions, and at high node positions under low temperature and short-day conditions, to ensure that the cut flowers maintain their excellent characteristics, the flowering node should be at least 10 nodes above. On the other hand, insufficient light also inhibits the differentiation of lateral branches, resulting in a decrease in the number of flower buds and poor formation of flower organs.Platycodon grandiflorus requires ample water during the germination period, but after germination, water should be controlled appropriately. Intermittent misting can be used to supply water during the seedling stage.3. Adult Seedling ManagementGrowth is slow in the early stage, and the growth rate increases significantly after 6 leaves. If the amount of fertilizer and water cannot be controlled well, it is easy to cause the stems to become thin and soft, leading to lodging or bending, reducing quality and affecting its commercial value. On the other hand, if the days are short and the New Year is coming, the plants will bloom. If the light is weak and the temperature is low, the plant's water requirement is also small; if the light is strong and the temperature is high, the plant's water requirement is large. Moreover, plants tend to grow towards light, so pots should be rotated in time to avoid severe phototropic growth.Platycodon grandiflorus requires strong light and long-day conditions for growth and development. The light during the seedling stage should be 13 to 14 hours, and there should also be sufficient light intensity for photosynthesis. After transplanting, 16 hours of light per day is generally better.Platycodon grandiflorus is a plant that likes fertilizer and can be fertilized immediately after transplanting with slow-release fertilizers or liquid fertilizers. Additionally, Platycodon grandiflorus has a high demand for calcium, and if the soil lacks calcium, plant tip burning can occur. Attention should be paid to the application of calcium fertilizers during production, and Ca(NO3)2 or CaCl2 can be applied.4. Flowering Stage ManagementThe flowering stage prefers high temperatures and requires higher temperatures, with 24°C to 28°C being optimal for growth, and it can tolerate temperatures above 36°C. Flowering is poor under overcast and insufficient lighting conditions, while strong light and long-day conditions result in better flower quality. Therefore, supplementary high-intensity lighting is needed in winter and areas with low light intensity. After the flower buds appear, water supply should be gradually reduced, and overhead watering should not be continued, as it is prone to adopt drip irrigation from the bottom.