How to choose orchid potting medium? A detailed guide to soil mixing methods for growing orchids

To grow orchids well, the potting medium is the foundation. How do you choose a potting medium suitable for orchid growth? Based on years of experience growing orchids, the author shares his personal views.

1. Matching the potting medium with the orchid pot. At present, most people choose clay pots, purple clay pots, ceramic pots, etc. for growing orchids. Because these orchid pots differ in breathability, the potting medium chosen for growing orchids also differs. Clay pots, because of their excellent breathability and drainage and good moisture retention, can use a somewhat finer potting medium; when choosing purple clay pots or ceramic pots for growing orchids, because of their poor breathability, in summer and autumn under the influence of the weather, the pots absorb heat quickly and dissipate it slowly, so a somewhat coarser potting medium can be used. In short, the potting medium must match the size and depth of the orchid pot and be determined by the type of orchid pot.

2. Selection of the potting medium. According to the author's experience, first, reasonably choose humus soil from the orchid's native habitat. Black humus soil containing dead branches and fallen leaves in mountain rock crevices, or humus soil from the surface of pine forest floors on mountains, is most suitable, as it can both increase the nutrients for orchids and benefit the growth of orchid roots. Second, mix in a small amount of brick granules. It is best to choose blue brick granules; before use, first soak the brick granules in water for 3 to 5 days to remove the alkaline substances and residual heat from the brick granules, thereby enhancing the breathability and water absorption of the brick granules themselves. Using them to grow orchids, the roots will not turn black or rot, and variegated-leaf orchids will not lose their variegation. Third, use coal cinders appropriately. Because coal cinders are produced by high-temperature burning and still contain large amounts of alkaline substances and residual heat after cooling, they must be soaked for several days before use to remove the alkaline substances from the brick granules, then left to dry for later use; coal cinders that have been tempered are absolutely harmless to orchids. Fourth, make skillful use of fired turf soil. Turf soil roasted at low temperature contains large amounts of phosphorus and potassium fertility, as well as small amounts of trace elements such as manganese, iron and calcium. If used to grow variegated-leaf orchids, the orchid plants are robust, the variegation rate is relatively high and it is relatively stable.

3. The potting medium ratio should be appropriate. If you choose a clay pot as the orchid pot and choose humus soil from the native habitat as the potting medium, the native humus soil should account for 70% of the mixed potting medium, and a small amount of charcoal pieces or brick granules should be used at the bottom of the pot. If you choose a purple clay pot or ceramic pot as the orchid pot and choose brick granules or coal cinders as the potting medium, a proportion of 40% to 60% is more appropriate, mixed with 30% to 40% pond mud, and a small amount of foam fragments should be used at the bottom of the pot. If fired turf soil is chosen as the main potting medium, the proportion can be between 60% and 70%, used mixed with charcoal pieces and brick granules.