Detailed Guide to Growing and Caring for Cymbidium ensifolium

　　2.1 Temperature:In winter, the temperature must not drop below 3°, otherwise frost damage will occur. Between 20° and 28°, growth is vigorous and the plant flowers and fruits. When temperature and humidity are suitable, most varieties can bloom twice a year, and some varieties known as Four Seasons Orchid can bloom four times. It cannot tolerate high temperatures above 32°, and below 0° it suffers frost injury, with the plant turning black and dying.

　　2.2 Humidity:Cymbidium ensifolium likes moisture but fears waterlogging, so the growing environment needs frequent misting to increase humidity. The ideal relative air humidity is 65-70%, and during the dry seasons of summer and autumn, the leaves should also be misted frequently. The minimum humidity should generally not be less than 50%, otherwise the leaf tips will dry out and turn yellow. During hot, humid weather in summer and autumn, ventilation should be strengthened to prevent root rot and stem and leaf rot.

　　2.3 Light:Cymbidium ensifolium likes ample diffused light and fears shade. The daily light intensity is generally most suitable at 8000-10000LX. In summer and autumn, shade 70-80% of sunlight; in winter and spring, shade 30-40%. For cultivation in a shed or glasshouse, use shade netting; for home cultivation, use ordinary light-filtering curtains. However, in winter and spring, when the daytime temperature is below 10°, full sun can be given to help raise temperature and promote sprouting and strengthen the plant's disease resistance.

2.4 Growing medium and mixing ratio:Cymbidium ensifolium has a well-developed, thick root system and has relatively high requirements for soil aeration. Therefore, the growing medium is often chosen mainly from coarse, hard granular materials. Among inorganic granular materials, choose small stones with a particle size of 7-10mm (without sharp corners), perlite, ceramsite, fired soil, orchid stone (lanhua stone), crushed brick pieces (without sharp corners), etc., using one or two of these in combination. For organic materials, choose peat soil, leaf mold, grass peat, fermented peanut shells, fermented sawdust, fermented raw wood shavings, decomposed tree bark, etc. When mixing the soil, the volume ratio of inorganic granular materials to organic materials is generally 2:1 or 3:2. German peat soil is of good quality, but its particle size is extremely small, so it is best to mix it in at no more than 30% of the total volume.

Because inorganic coarse granular materials, once filled in, have a stable aggregate structure, with sufficient gaps between the large aggregates for air storage and circulation (forming capillaries), and combined with a certain amount of relatively stable organic matter and fertilizer, the growing medium and ratio prepared in this way can drain water and allow air through while containing organic matter, which is beneficial for daily management and the healthy growth of Cymbidium ensifolium, and can reduce the probability of disease. This modern growing medium ratio suits the physiological structure and natural habits of orchids, is more scientific and advanced than how the ancients grew orchids, is more suitable for large-scale cultivation, and saves effort and trouble.

Of course, it can also be grown entirely in sphagnum moss or moss, but water and fertilizer management is more difficult, and a slight mistake or harsh environment can cause root rot. It can also be grown in a medium made from yellow sand soil and sawdust in equal proportions plus an appropriate amount of coarse river sand.

In short, growing medium sources are very broad and the ratios are various. As long as the orchids grow well, any medium can be a good medium. However, it is not recommended to use ordinary planting soil or clayey soil to grow orchids, as they have poor aeration and easily compact into clods.

There is no universal growing medium or ratio. One should adhere to the principle of adapting to local conditions and find the medium and ratio suited to one's own cultivation habits and environment. Generally, in hot, humid, and rainy climates, the proportion of coarse granular material should be increased; conversely, in low-temperature and dry climates, the proportion of fine organic material should be increased. Generally, these two climates alternate through the year, so repotting and changing the soil is usually done in late spring and late autumn to respond to climate changes, adjusting the medium formula to meet the needs of orchid growth in different seasons and reduce the probability of disease.

　　2.5 Pots:Unglazed ceramic pots or clay pots with good aeration are best, porous plastic pots are second, and glazed porcelain pots have the worst effect.

　 2.6 Watering:There is no fixed pattern for watering orchids; it depends entirely on the ambient temperature and humidity, the soil's water content, and wind. Unless water is deliberately controlled before flowering to force blooming, the potted soil and medium should always be kept moist but not wet. The so-called "water when dry, stop when wet" saying is actually unscientific, as it is impossible to gauge the dryness and moisture of the medium.

Orchids are difficult to grow because of the special nature of their roots, so growing orchids requires growing the roots well. The key reason beginners fail with orchids is that the roots are not grown well. Part of the reason the roots are not grown well is related to the medium, but mainly it is failure to grasp the timing and amount of watering. When it is time to water, if you do not water or do not water thoroughly, the roots dry out and are damaged (water molecules inside root cells osmose outward into the medium and the roots wither and die); when it is not time to water, if you water heavily every day, the roots drown and rot (anaerobic respiration in the roots produces lactic acid and alcohol poisoning, and anaerobic bacteria multiply massively). This is also the origin of the saying that watering takes three years to master.

Orchid roots are fleshy roots, mostly composed of living cells, unlike the roots of many plants, which are mostly lignified except for the root tip. Therefore, the living cells of orchid roots have a demand for oxygen (living cells need large amounts of oxygen for aerobic respiration to sustain life) far greater than other root systems. Thus orchid roots have high requirements for medium aeration, especially Cymbidium ensifolium with its thick roots, which has even higher requirements. Moreover, orchid roots have no root hairs and rely entirely on cell osmosis to absorb water outside the cell membrane, and the water must be on the roots. At the same time, gravitational water and adsorbed water cannot be used; only capillary water can be used by the roots, and if it is even slightly farther away, none can be absorbed. It can be seen that water and air are a contradictory pair: more water in the medium necessarily means less air, and more air necessarily means less water, and neither extreme works. This is the principle behind watering promptly and thoroughly, and also the principle behind using coarse medium.

According to experiments, modern plant physiology theory holds that when the water content of a plant growing material is 70 percent, it is the best time for cultivation. For orchids, when the medium's water content is below 60%, it affects normal growth and development. The author does not know what medium these data were measured with experimentally, because different materials have different water absorption rates, that is, different water contents, and their rates of moisture loss differ, so these data cannot serve as a basis for watering orchids. The most intuitive and objective method is to insert a fresh, non-rotted small bamboo stick or wooden stick to a depth of more than 5 cm below the medium surface and observe the change in color depth to confirm the degree of dryness and moisture of the soil, thereby determining when to water. Of course, advanced instruments can also be used for measurement.

It is worth noting that the watering cycle and amount for orchids are closely related to their different physiological stages. During the vigorous vegetative growth period, water more and water frequently. During hot and humid weather, before flowering, and during the flowering period, control water and water less or even not at all. After all, orchids rarely die from drying out but often drown, and orchid roots have a very strong drought tolerance. As long as the environmental humidity is suitable, some orchid varieties will not wither and die even if not watered for a month.

My basic watering practice is: when temperatures are low in winter and spring, water thoroughly once every 7-10 days, in the morning or near noon, shortening the interval when the air is dry. When temperatures are high in summer and autumn, water thoroughly once every 3 days, after the sun sets in the afternoon. Do not water on rainy days, and do not water during the high heat of the afternoon. In spring and summer during sweltering thunderstorm weather, water to cool down and prevent root rot, while increasing ventilation. If there is naturally no wind, use exhaust fans or electric fans for ventilation.

　 2.6 Ventilation:Needless to say, this is a basic requirement for growing orchids, determined by their natural attributes, and closely related to orchid root aeration and leaf respiration. At the same time, ventilation can inhibit the growth of pathogens, especially playing a major role in inhibiting the growth of certain anaerobic bacteria. It is best to have ventilation on all six sides, that is, the six faces of the flower pot: top and bottom, left and right, front and back should all remain ventilated, with no obstructions. With good ventilation, orchids have fewer diseases and the plants are robust.

Now that the issue of watering has been explained clearly, let us then discuss the issue of ground qi for orchid growth. Ground qi was once described very mysteriously, but in fact, from the perspective of plant soil science, it is the soil's moisture (gaseous water) and heat (soil heat storage), and can also include the air conditions and fertility within the soil. We know that the wild environment of orchids is basically shaded, sunny, ventilated places with deep leaf mold, basically under forest canopy on southeast-facing slopes, with abundant rainfall, and they rarely grow in low-lying, waterlogged, shaded places without sunlight (which are good places for mosses and ferns to grow). Such places are places with good ground qi, warm in winter and cool in summer, with suitable humidity and temperature, suitable water, moist but not waterlogged. But for indoor potted orchids, because the area and volume of the potting soil are extremely limited, there is no ground qi to speak of, and "ground qi" can only be artificially created. The many factors mentioned above must be regulated manually, which is also the difficulty of indoor home orchid growing.

　　2.7 Fertilizer:Orchids are plants that like dilute fertilizer. Because the prepared medium contains little and incomplete nutrients, dilute fertilizer must be applied frequently. Fertilizer sources are also very broad, with many types of homemade organic fertilizers and commercial fertilizers. For home orchid growing, it is recommended to use commercial compound fertilizers to reduce unnecessary trouble and prevent polluting the indoor environment and breeding pests. To save effort and trouble, it is recommended to use compound granular slow-release fertilizer, evenly placed about 3 cm below the soil along the pot edge, without touching orchid roots or pseudobulbs, 2-3g per pot. Add some special fertilizer at the appropriate time. The following are fertilization guidelines summarized by orchid growers, for reference:

Sprouting period: Dilute nitrogen fertilizer according to the ratio, then dilute another 8-10 times. Ensure fertilizer with each watering, and supplement foliar spraying with phosphorus and potassium fertilizer 5-6 times per month. Ensure that the orchid plant absorbs fertilizer promptly after waking up, laying a good foundation for seedling development. Fertilize frequently and dilute.

Spring growth period: When the minimum temperature reaches above 12 degrees Celsius, apply nitrogen and potassium fertilizer in equal halves at the diluted ratio once as a root drench, prompting the mother plant's pseudobulb cells to divide rapidly and differentiate new shoots. This period is the golden season for orchid plant growth, and timely fertilization is crucial in the year's production. Do not fertilize too concentratedly and damage the orchid plant; strictly follow the instructions and fertilize at a slightly reduced ratio. Homemade cake fertilizer and the like are best used after experimental observation; do not be too impatient. Because the content of such fertilizers is hard to judge accurately, losses are easily caused. Generally, diluting 500 times will not be a problem (not absolute). As the temperature gradually rises, the new shoots rapidly expand; supplement with phosphorus fertilizer sprayed on the leaves. Maximize light exposure to fully mobilize and bring into play the plant's physiological functions, rapidly absorbing and converting fertilizer. After fertilizing, carefully observe the plant's growth. If fertilizer damage is found, promptly flush with water or repot.

Spring vigorous growth period: Because we recently applied root fertilizer at the diluted ratio, most media still contain some residual fertility, so there is no need to deliberately fertilize again. Simply apply at 1/8 of the ratio together with watering. Spraying foliar fertilizer once every 2-3 days does no harm to the normal growth and development of the orchid plant. For purely coarse medium, one supplementary root fertilizer can be given.

Stagnant growth period. During this period, because the temperature is too high, most orchid plants stop growing. Even if the current year's new seedlings grow, they grow very slowly, while the parent plants are breeding flower buds at this time. Therefore, at this time it is still necessary to spray some phosphorus fertilizer to promote flowering in the parent plants.

In autumn, growth is vigorous. During this period, the current year's new shoots are basically mature seedlings, with a few half-mature seedlings, and after autumn they can all grow into large, strong seedlings. The flower buds of the parent plants have basically emerged, and a few new strong seedlings occasionally produce flowers. For those with flower buds, stop root fertilizer, and halve foliar fertilizer as appropriate. For orchids without flowers, apply phosphorus and potassium fertilizer once as a root drench at the diluted ratio, ensuring that the current year's new pseudobulbs are large, so that there is hope of flowering next year.

During the winter dormancy period, orchid plants basically stop growing. For orchid plants maintained on balconies or indoors, a small amount of foliar fertilizer is still needed, generally 2-3 times per month, mainly phosphorus and potassium fertilizer, sprayed at noon on clear days.

Also, Xu Dongsheng's monograph contains similar detailed introductions; one can understand by reading the book oneself.

　　2.8 Pest and disease control: ⟧37⟧Home-grown orchids have very few insect pests. The main thing is to do good sterilization and disinfection work. Commonly used drugs include thiophanate-methyl, carbendazim, etc., using the right medicine for the condition. Especially in hot and humid seasons, doing sterilization once every half month is not too much. Mainly dilute according to the drug instructions and spray on the leaves. For specific disease identification and measures, see the book "Atlas of Orchid Pest and Disease Diagnosis and Treatment."Home-grown orchids have very few pest problems; the main thing is to do a good job of sterilization and disinfection. Commonly used drugs include thiophanate-methyl, carbendazim, and others, applied according to the specific problem. Especially in hot and humid seasons, doing a sterilization treatment once every half month is not too much; mainly dilute the drug according to the instructions and spray it on the leaf surface. For specific disease identification and measures, see the book "Atlas of Orchid Pest and Disease Diagnosis and Treatment".

That is all for the cultivation and management techniques of Cymbidium ensifolium. Please correct any inappropriate points, and let's exchange views if there are questions.