How to grow orchids? Good ventilation is key

Orchid plants mostly become diseased because the temperature and humidity of the micro-environment are too high, and the stuffy, unventilated conditions allow pathogens and pests to spread quickly, with aphids, whiteflies, scale insects, brown spot disease and southern blight being the most obvious.

Ventilation of the site and the shade shed. The site should be as spacious as possible and located in a high place. The flower benches can be built from bricks and stones, or empty flower pots can be placed upside down with the orchid pots on top, so that the orchid pots are 20 cm to 40 cm above the ground; especially in poorly ventilated places, the orchid pots should be placed as high as possible. Bamboo blinds and bamboo fences used for the shade shed are cheap and good, and provide good ventilation.

Poor indoor ventilation and air exchange will change the proportional relationship among the various gases in the air, increasing harmful gases and reducing useful gases, which affects the growth and development of orchids, makes them prone to mold and rot diseases, and may even cause poisoning. In houses, closed plastic sheds or glass sheds, especially those heated with coal, when the indoor temperature exceeds 10°C, the windows should be opened or the film lifted every day. In winter, in rooms sealed tightly on all sides, an electric fan should also be used to provide directed exhaust ventilation when the temperature is high at noon. The temperature in a greenhouse is generally higher at the top and lower at the bottom, so the air inlet should be at the lower part and the air outlet at the upper part, so that the ventilation speed is fast and harmful gases are removed more thoroughly. While paying attention to ventilation, it should be combined with spraying water, properly handling the relationship among ventilation, heat preservation and moisture retention, and preventing cold wind from blowing directly. The density of orchid pots placed indoors should be sparse rather than dense, and sufficient distance should be maintained; if the space is narrow, the flower benches can be built into stepped shapes. Attention should be paid to frequently washing the surface of the orchid pots with water and spraying the front and back of the orchid leaves to ensure that the stomata remain unobstructed.

Ventilation of pots and potting soil

1. Orchid pots should preferably be tall, high-footed, thin-walled clay pots with strong air permeability; orchid pots with many holes in the walls and bottom can also be chosen.

2. The planting material or potting soil should preferably be applied in layers. If potting soil is used, 2 to 3 small bricks can be used to cover the bottom hole of the pot, then a 3 cm thick layer of lump charcoal is spread on top, then a mixed soil of decomposed humus soil and river sand is filled in up to 1/2 of the pot height, then a 3 cm thick layer of burned cinder is added, and above that mixed soil is again covered up to the pot rim, so that the orchid pot has an environment in which gas can easily circulate.

3. The number of plants planted in each pot should not be too many. If there are many plants and the leaf clusters are dense, they should be repotted and divided in time, and weeds, diseased leaves and dead leaves in the orchid pots should be frequently removed to facilitate ventilation.