The Latest Method for Propagating Cattleyas by Division and Key Points for Daily Care
This popular mass-market orchid, the Cattleya, was discovered on the tropical American continent, and there are now 45-50 species and countless hybrid varieties. Among tropical orchids, the Cattleya has the largest flowers and the most brilliant colors, and internationally it enjoys the reputation of "King of the Tropical Orchids." Through cross-breeding by horticulturists, nearly a thousand horticultural varieties have already been developed. The Cattleya is native to the Honduras and Belize regions of Central America and Guatemala, and it is extremely adaptable.
I. Introduction of Cattleyas
Cattleyas are native to the tropical and partly subtropical regions from Central America to South America. Generally speaking, most of the Cattleyas popular on the market today are horticultural varieties bred through multiple generations of hybridization and selection, with stable traits and ease of cultivation.
For growers who are just starting to cultivate Cattleyas, they should consider such aspects as flowering period, flower shape, growth habits and cultivation cost when selecting varieties whose flower color and shape suit Chinese aesthetics, whose flowering period coincides with major domestic holidays, that have good reblooming ability, strong disease resistance, and tolerance to cold and high temperatures (for native species, it is recommended to introduce artificially selected polyploid plants).
At present, most of the Cattleya seedlings in mainstream orchid nurseries in China are introduced from Taiwan, China, which offers the best value for money, and few are introduced from Europe, the United States or Japan. When introducing plants, attention should be paid to the original source of the seedlings and the habits of the parent plants, as well as whether there are problems such as pests and diseases.
II. Site Planning
The Cattleya is a perennial herbaceous plant, with bulbous or club-shaped pseudobulbs at the lower part, 1-3 leathery leaves at the top, and creeping stems that can spread in multiple directions. It takes 2-4 years from removal from the flask to flowering. The Cattleya is an epiphytic plant, and its root system consists mostly of aerial roots. Compared with other tropical orchids, it is relatively light-loving and drought-tolerant, and slightly cold-tolerant.
Its growing environment should be warm and humid, bright and well ventilated, with a slightly acidic, airy substrate. Therefore, when choosing a site to build a greenhouse, one should select an area that is flat, has ample light, convenient transportation, good ventilation and power supply facilities. Generally, the basic equipment of a greenhouse for growing Cattleyas needs bidirectional exhaust fans, equipped with a water curtain and multi-layer shade netting, and in winter, supplemental lighting and heating facilities should be provided. The seedling bed should be set up more than 1 m above the ground, with a mesh surface, on which seedling plug trays and containers can be placed; some varieties can be grown by hanging.
III. Cultivation Methods
1. Selection of substrate and growing containers: Cattleya roots are aerial and like moisture, so a growing medium with good air permeability and drainage should be chosen. Most Cattleyas on the market are grown using sphagnum moss; this method has low cost and fast growth, but the substrate tends to rot and clump. A small number of flower companies also use pure bark for planting; plants grown this way are robust, but the cost is relatively high.
A mixed substrate can also be prepared by oneself. The pH value of the substrate should be controlled at 5.5-6.5, weakly acidic. It is generally bark mixed with orchid stone, mixed with fired soil, mixed with Satsuma soil, in a ratio of 1:1:1:1. In choosing growing containers for Cattleyas, one should try to meet the principles of light transmission, air permeability, sufficient drainage holes at the bottom, and not being too large. Generally, ceramic pots are best, transparent nutrient cups second, and plastic vessels last. When planting, there should be plenty of bottom padding, and deep planting must be avoided.
2. Temperature, humidity and light management: Although Cattleyas are drought-tolerant and cold-tolerant, they like a high-temperature, high-humidity environment. The suitable temperature during the seedling stage is around 25°C, and during the growing period of large seedlings the temperature can be controlled at 15-30°C. In winter, the room temperature needs to be kept no lower than 15°C to prevent frost damage and failure to bloom, and 2-3 h of supplemental lighting is needed each day.
During the seedling stage, humidity should be controlled at around 80%, and it can be maintained by spray humidification, water curtain humidification, and spraying the ground to cool and humidify; during the mature seedling stage, humidity should be controlled at 60%-80%. During the seedling stage, light should be controlled for Cattleyas; from spring to autumn, use shade netting with a shading rate of 60%-70% for shading. From large seedlings to the flowering stage, management can be more extensive, and in summer a 50% shade net is sufficient.
3. Water and fertilizer management: The growing period of Cattleyas is from spring to early autumn. Generally, sufficient water should be ensured at the beginning of the growing period. In spring and summer, when new shoots sprout, attention should be paid to timely water supplementation. Generally, water when the substrate surface looks dry (once every 2-3 d for sphagnum moss; for bark and mixed substrate, water once each at 9:00 and 15:00 every day; the same below). Water thoroughly each time, and try to maintain the two extremes of dry and wet in the substrate. In autumn and winter, watering should be controlled (once every 4-5 d for sphagnum moss; once every 2-3 d for bark and mixed substrate), and it is enough to keep the potting soil moist.
During the growing period, Cattleyas should be given light but frequent fertilization. Generally, a mixed controlled-release fertilizer with a nitrogen-phosphorus-potassium ratio of 1:1:1 is used. During the growth stage of large seedlings, apply 1.5 g each time, with additional fertilization once every 7-14 d; when entering the flowering period, a flowering-stage fertilizer with a higher phosphorus and potassium ratio should be used; after flowering, the frequency and amount of fertilization should be reduced. During the growth process, a special orchid foliar fertilizer should also be used as a supplement, generally sprayed once every 7 d, with the mixing ratio used according to the parameters provided by different brands.
4. Propagation by division: Cattleyas can be propagated by division after growing for 3-4 years following removal from the flask. Generally, ensuring that each clump has 3-5 old pseudobulbs and 1-2 new shoots makes it easiest to grow and flower. Note that any gardening tools that come into contact with Cattleyas during division must be disinfected to prevent disease infection.
Division should be carried out before April, when new shoots have just sprouted. During division, care should be taken to cut off shriveled pseudobulbs, remove old and rotten roots, remove weak shoots, and keep the most robust new shoots on the main stem. All wounds should be smeared with sulfur powder for disinfection, and planting should be carried out after the wounds have dried. When planting, the new shoots should be planted near the center of the pot to ensure that the new plant has enough space to grow. Large plants and long-stemmed plants should be staked to prevent lodging. Cattleyas should not be divided frequently or excessively, otherwise the plant's flowering ability will be greatly weakened.
5. Pest and disease control: Common diseases of Cattleyas include anthracnose, soft rot, southern blight, and viral diseases, while common pests include scale insects, slugs, and red spider mites. During the cultivation stage, pest and disease control should focus on prevention. In ordinary times, it is recommended to spray with thiazine-methidathion emulsifiable concentrate at 800-1000 times dilution, generally about once every 7 d; every 7 d, combine this with 75% chlorothalonil wettable powder at 2000 times dilution for control.
During the flowering period, it is not recommended to treat pests and diseases with medication; manual removal of diseased parts is recommended. For viral diseases, there is only prevention. Generally, keep the environment clean and well ventilated, disinfect tools thoroughly, disinfect plants thoroughly, and introduce plants from regular disease-free sources. Once a diseased plant is found, it should be burned and destroyed immediately, and the surrounding plants should be isolated for observation.
6. Flowering period management: During the flowering period of Cattleyas, attention should be paid to keeping temperature and light constant and maintaining ventilation, so as to ensure normal flower development and coloration and to prevent disease spots from affecting ornamental quality. Large-flowered, multi-flowered, and long-stemmed varieties should be staked to prevent lodging. The flowering period of Cattleyas can last 30-45 d, which is relatively short compared with other tropical orchids such as Phalaenopsis, so it is best to sell them out of the greenhouse when the first flower bud opens.
The flowering period of Cattleyas consumes a large amount of the plant's nutrients, so additional fertilization should be given about 7 d after the plant begins to flower. When spraying the plant during the flowering period, try not to get water on the flowers to prevent disease.