Detailed Explanation of Key Techniques for the Cultivation and Management of Phalaenopsis Test-Tube Plantlets
I. Acclimatization and Removal from Flask for Planting of Test-Tube Plantlets
1. Acclimatization To increase the survival rate of Phalaenopsis test-tube plantlets, the plantlets must first be strong. Before removing the plantlets from the flask, they must first undergo acclimatization. When the plantlets have three leaves, place them in diffused sunlight and expose them evenly for about 20 days, so that the test-tube plantlets grow more robustly and can adapt more quickly to external environmental conditions after being removed from the flask.
2. Removal from Flask Great care must be taken when removing the plantlets from the flask. First pour a small amount of water into the culture flask, then gently shake the flask. After the solid culture medium is loosened, use long tweezers to take out the orchid plantlets, minimizing damage to the orchid roots and leaves.
3. Planting After being removed from the flask, the plantlets are dried in the shade and then planted in small white transparent plastic pots with a diameter of 5 cm that have good air permeability, with 1 plant per small plastic pot. The substrate is best as sphagnum moss, with a small amount of small crushed brick pieces placed in the lower part to allow water drainage and air permeability. Before planting, the substrate should first be disinfected. The sphagnum moss should not be too wet or too dry; a simple method is that it is suitable when no water can be squeezed out by hand. When planting, the sphagnum moss should not be too tight or too loose, because too tight is not conducive to the permeability of the orchid roots, while too loose makes the orchid plant unstable and causes the sphagnum moss to absorb too much water, easily leading to root rot. It should also not be planted too deep; it is suitable to expose the stem base of the orchid plant.
4. Repotting According to the growth of the orchid plantlets, repot in a timely manner. When the orchid roots fill the pot, repotting can be done to facilitate plant growth. Generally, after 4-6 months out of the flask, carry out the first repotting using a white transparent plastic pot with a diameter of 8 cm, and after another 10-12 months, repot once more using a white transparent plastic pot with a diameter of 12 cm. When repotting, cut off rotten roots and diseased or damaged leaves. If the substrate is still relatively good, the original substrate can be retained and only some substrate added around the outside, without damaging the orchid roots.
II. Cultivation and Management
1. Temperature Whether the temperature is suitable or not is the key to good growth of Phalaenopsis. The suitable growth temperature is between 18°C-28°C, and the absolute low temperature should not be lower than 10°C, otherwise it is prone to cold damage, causing leaf drop, yellowing and shedding of flower buds, and even rot and death of the whole plant. Large-scale cultivation of Phalaenopsis must have a greenhouse in order to pass through winter safely. When the summer temperature exceeds 30°C, Phalaenopsis will be in a semi-dormant state. At this time, if watered too much, it will cause rot of the plant's roots, stems and leaves. Therefore, in the process of cultivating Phalaenopsis, cold protection is needed in winter and spring, with insulation facilities such as covering with plastic film and using heaters to warm the orchid shed, to prevent cold damage; in the extremely hot summer, cooling measures should be taken, such as spraying cool water on the roof of the flower shed, pouring ice water under the flower rack, and using fans to blow air to achieve the cooling effect. For Phalaenopsis in the growing period, the daytime temperature should be between 25°C-28°C, and at night it is best between 18°C-25°C. Entering the winter dormant period, a temperature not lower than 10°C will not only avoid cold damage to Phalaenopsis, but instead help its flower bud differentiation and promote blooming when spring arrives.
2. Light In its place of origin, Phalaenopsis is a typical shade-tolerant plant. However, it cannot be too densely shaded, otherwise the plant grows weakly, the leaf color becomes dark green with spindly growth, the leaves droop, it is difficult to flower, and it is prone to pests and diseases. Therefore, a certain amount of diffused light is needed: 10000-15000 lux for small plantlets, and 12000-20000 lux for medium and large plantlets. Appropriate light gives high photosynthetic efficiency, benefits orchid plant growth, and can make the leaf color bright green, the leaf flesh thick, the leaves firm, the plant robust and promote flowering. But it cannot be exposed to strong sunlight; intense light will cause scorching on the leaves. During the growing period in summer and autumn, shade 50%-70%; in spring and winter, shade appropriately. The light in the whole orchid shed should be kept uniform so that the plants grow evenly. If some corners cause biased growth of plants due to uneven light, frequently adjust the orientation of the orchid plants.
3. Water Phalaenopsis growth requires relatively high air humidity. During the growing period, maintaining humidity above 80%-90% gives the best effect. During the flower bud differentiation period of Phalaenopsis, water should be controlled to benefit flower bud differentiation. When watering, try to avoid leaving standing water on the leaves, especially in cold winter, because the leaf flesh tissue at the place with standing water is easily damaged by freezing, which then causes leaf rot. Therefore, in winter after watering, if water droplets remain on the orchid leaves, they must be wiped dry. In the spring and summer growing period, water once a day or spray 2-3 times. In the rainy season when the air is humid, water less. In winter, it can be reduced to watering once every 2-5 days, and spraying can be stopped; in principle, keeping the substrate slightly moist is sufficient. Phalaenopsis has strong drought tolerance. When the winter temperature drops below 10°C, watering may be omitted to prevent cold damage. The cultivation substrate must not accumulate water, as water accumulation easily causes root rot.
4. Fertilization Mainly use chemical fertilizers. Commonly used ones include chemical fertilizers and some special orchid fertilizers, such as Hyponex and Peter's. Follow the principle of applying thin fertilizer frequently. Fertilizer used for small plantlets should also be diluted to a relatively large multiple to prevent fertilizer damage. Use a 1000-fold diluted solution to drench or spray 1-2 times per week during the peak growing season, and once a month during the slow growth period.
5. Ventilation Phalaenopsis is an epiphytic orchid with aerial roots. The aerial roots not only have a respiratory function but can also carry out photosynthesis because the aerial roots contain chlorophyll. Phalaenopsis requires extremely high ventilation and air permeability. For large-scale cultivation, the orchid plantlets must be placed on flower racks about 50 cm above the ground. In the extremely hot summer, electric fans should be used to blow air, and the orchid plants should not be too dense, maintaining ventilation and air permeability throughout the orchid shed. Only in this way can Phalaenopsis grow well and prevent the occurrence of pests and diseases.
6. Flowering Period Management
The flower bud differentiation of Phalaenopsis is mainly affected by temperature. After passing through the high summer temperatures and entering autumn, lower nighttime temperatures can promote flower bud differentiation. Maintaining a day-night temperature difference of about 10°C, flower buds can form after about one and a half months. When the flower buds grow to 8-10 cm, raise the temperature to 20°C-28°C to facilitate the rapid growth of the flower scape. At this time, the temperature can be adjusted as needed to control the flowering period, but the temperature must not be higher than 30°C. During the bud stage, if the time above 30°C is too long, it will lead to bud failure, that is, the development of flower buds is hindered, causing the flower buds to stop growing and dry up. The temperature also must not be too low. If it is below 15°C, the flower scape almost stops growing, and may even suffer cold damage causing bud drop. When the flower branches of Phalaenopsis elongate, iron stakes can be inserted for support, or the branches can be bent and shaped as needed. They can also be planted together in pots according to flower color and plant type. When potting, the original culture bag can be left in place without removing it, so as not to damage the orchid roots. After flowering, do not pour water onto the flowers.
III. Pest and Disease Control
The flowers and leaves of Phalaenopsis both have high ornamental value. After being damaged by pests and diseases, the leaves retain disease spots, notches and so on, affecting the ornamental value and economic value of the orchid plant. Therefore, doing a good job in the prevention and control of Phalaenopsis pests and diseases is an important part of successful Phalaenopsis cultivation. In the cultivation process, the key is prevention: maintain the ventilation and light transmission of the orchid garden, adopt scientific cultivation measures, strengthen management and care, enhance the disease resistance of the plants, and prevent the occurrence of pests and diseases. Once pests and diseases are found, spray pesticides for control as early as possible, which can achieve relatively good results.