Classics of raising orchids in ancient and modern times

Author: Chen Gui (Compiler)
Publisher:
Publish Date: 2002-03-01
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16. Repotting Orchids
Repotting orchids refers to changing the potting medium and replanting. Repotting is a routine task in orchid cultivation, typically done once a year. Some orchids may be repotted every two to three years, while others may be adjusted earlier or later based on specific conditions. Repotting is an essential and frequent activity for orchid growers. After planting orchids in a pot, over time, if the planting depth is inappropriate, the pot or medium is unsuitable, or the growth direction needs adjustment, it is necessary to replant the orchid. This repotting and replanting process involves renewing the orchid pot and altering the original cultivation conditions to further improve the orchid's growth environment, allowing for more vigorous growth. The primary purpose of repotting is to discard the old and embrace the new—removing the old medium and using fresh soil for cultivation. Here, we introduce the typical steps for repotting.
Repotting Time. There are two ideal times: shortly before or after the Qingming Festival and shortly before or after the Autumn Equinox. After Qingming, seedlings begin to grow, and after the Autumn Equinox, flower buds develop. Repotting during these periods is beneficial for orchid growth. Summer and winter are generally not suitable for repotting.
Repotting Preparation. Ten to twenty days before repotting, reduce watering to allow the potting medium to dry slightly. If the medium is wet when repotting, it may damage or break the orchid roots, and the wound may rot. Additionally, wet soil can clog the pseudobulbs, making it difficult to see new growth points, and may rub off seedlings or flower buds.
Repotting and Soil Removal. Use wooden or bamboo strips to loosen the soil around the pot edges. Tilt the pot and shake out the loose soil until most of the edge soil is removed, then carefully remove the orchid and soil together. If the orchid has many roots, avoid damaging them by gently breaking the pot if necessary, preserving the orchid rather than forcefully extracting it.
Replanting the Orchid. After removing the orchid, trim the roots and leaves. Cut off dead and rotten roots. Some orchid roots may have a dry outer layer but still have a living core. Trim black cores, but retain white or yellow cores, which are alive and help absorb water and support the plant. If division is necessary, identify the natural division points (mouths) for separation.
Placing the Orchid in the Pot. Position the orchid in the pot according to its growth direction. New seedlings typically emerge from the stronger side, which indicates the orchid's growth direction. Place the older growth near the pot edge, while the stronger growth faces the center of the pot. This positioning ensures that new seedlings continuously develop toward the center, promoting healthier growth.
Covering the Soil. After determining the orchid's position, begin covering the soil. Use one hand to stabilize the orchid while using the other to fill the soil. When the soil reaches the top of the roots, gently lift the orchid to straighten the roots before continuing to cover the soil. When the soil reaches the base of the leaves, use both hands to lightly insert the fingers into the soil around the roots, ensuring the soil contacts the root edges, then add another layer of soil.
Watering After Repotting. Before repotting, ensure the potting medium is slightly dry. After repotting, do not water immediately, nor spray water. Wait a week before watering and spraying again. Some orchid growers argue that repotting can be done at any time, which is true. Orchids have fleshy roots and can tolerate being out of and back in the pot for extended periods, making repotting flexible. However, stability is key—repotting is both necessary and stressful for orchids, so it is better to repot less frequently. Some growers choose not to repot but instead replace half of the potting medium annually without disturbing the roots or leaves. This half-repotting method is worth emulating.
Reflection: Repotting involves changing the medium, with orchids repotted in spring and autumn. Repotting too often disrupts growth, while less frequent repotting promotes stable growth.
17. Orchid Greenhouse
An orchid greenhouse refers to building a dedicated structure for growing orchids. Orchid growers with a significant number of plants often construct greenhouses away from their homes to specialize in orchid cultivation. Currently, the orchid industry has become a thriving economic sector, and many households or growers seeking greater benefits in the orchid trade invest in building dedicated greenhouses—a practical approach.
In Dali, there is an orchid garden that houses over 1,000 orchids in a greenhouse. The garden covers 1.8 acres, with 0.6 acres dedicated to the greenhouse. The greenhouse faces south with a northern orientation. It is 80 meters long from east to west and 40 meters wide from north to south. The northern wall is 3.6 meters high, sloping downward toward the south, with the southern wall made of glass windows. Inside, three rows of orchid shelves are arranged. The middle row is an "H"-shaped ladder shelf, with a base height of 1 meter and shelf heights ranging from 1 to 8 meters. The southern row is a platform shelf, while the northern row is a sloped ladder shelf. Orchid pots are arranged in tiers, creating a green canyon. Doors are installed on both sides for ventilation. The ground is covered with sand and stones, maintaining humidity and shade. Inside the greenhouse, flowers bloom in a riot of color, and leaves grow lushly, giving the impression of walking through a tranquil forest.
Growing orchids in a greenhouse provides an optimal environment, reduces diseases, and enhances cultivation success. Greenhouse construction can vary in size based on cultivation plans and scale. Bamboo or steel greenhouses can be built, with heights not less than 3 meters. The ground can be covered with sand, stones, or bricks, allowing for moist or dry conditions. Orchids can be placed on shelves or on the ground.
For urban growers with limited space, such as balconies or small courtyards, building a greenhouse with shelves is a solution. One approach is to construct sloped ladder shelves. Typically, shelves measuring 2 meters long, 1.6 meters high, and 1 meter wide are suitable, as they are easy to place, move, and reconfigure. For example, a 1.6-meter-high shelf with a 1-meter base and three steps, each 20 centimeters high and 30 centimeters wide, can accommodate 18 orchid pots. Growing orchids profitably with 18 pots is feasible.
Another approach is to build multi-level shelves. These consist of two vertical ladders placed on the ground and connected. Each ladder is 1.8 meters high, 30 centimeters wide, with a base height of 40 centimeters and middle and upper platforms each 60 centimeters high. Between the ladders, wooden boards are placed to hold orchid pots. The boards can be adjusted in length. The space occupied by the shelves is minimal, allowing for flexible arrangements. For example, on a 1-meter-wide balcony, the shelves occupy only one-third of the width, leaving two-thirds of the space for cultivation and appreciation.
Reflection: Building a greenhouse with shelves ensures good airflow, while on balconies, ladder shelves can accommodate many orchids.
18. Temperature and Humidity for Orchids
Temperature and humidity refer to the environmental conditions required for orchid cultivation. Orchid growth is closely related to temperature and humidity levels. High temperatures and humidity promote rapid growth, while extreme high or low levels can harm the plants. Controlling temperature and humidity is a key challenge for orchid growers.
In natural conditions, terrestrial orchids begin growing at temperatures above 16°C and slow down when temperatures exceed 28°C. Humidity is generally optimal between 40% and 70%. High temperatures combined with high humidity can further stimulate growth. Epiphytic orchids require higher temperatures and humidity. If conditions are not met, they may grow leaves but fail to produce flowers.
Among terrestrial orchids that bloom in spring, the flowering period requires lower temperatures. Cool conditions promote the growth of flower spikes, while high temperatures delay them. The ideal flowering temperature range is between 16°C and 6°C.