How to Use Decayed Wood Chunks as a Filler Material

Adapting to the aerial-root-loving nature of orchid roots and finding ways to improve the permeability of the orchid pot is the key to growingorchidswell. The traditional approach is to grow them in loose, fertile humus soil and fill the bottom of the orchid pot with some water-draining, moisture-retaining, breathable medium to meetthe orchid'sphysiological needs. Therefore, the choice of what kind of medium to use as filler matters greatly; improper use can lead to serious mistakes, causing the plant to grow weak in mild cases, or even the death of the entireorchidplant in severe cases. In the past, following the practices of those before me, I first used broken bricks, tile fragments, furnace slag, charcoal, and the like, which achieved certain results. But after years of practice, I found their shortcomings are obvious and cannot fundamentally improve the limitations of the orchid pot. Broken bricks and tile fragments absorb water, retain moisture, allow air through, and are economical, but they are heavy with high density, dissipate heat relatively slowly, often have a pH above 7, and contain no organic matter, so they cannot provide organic nutrients for orchids. Charcoal is light with low density, and its pH is equal to or greater than 7. Because it has been carbonized, its organic matter is destroyed, and its other properties are the same as bricks and tiles. Obviously, the above media only provide permeability but no fertilizing effect, and must undergo acidification treatment when used. The traditional approach only considers improving the permeability of the orchid pot, and fails to comprehensively address the limitations of poor aeration, small nutrient area, and poor fertilizer retention of the orchid pot. At present, the soillesscultivationmethods adopted in Hong Kong, China and Taiwan, China as well as abroad, although their starting point is to address the shortcomings of the orchid pot and attempt to create a favorable ecological micro-environment for orchids, cannot be promoted and popularized in homeorchidgrowing in the short term due to high cost, inconvenient operation and management, relatively unsafe use, and the lack of systematiccultivationexperience in China. In view of the above reasons, I was inspired by the characteristic of orchids growing in secluded valleys and preferring to grow alongside decayed wood in the humus layer, and in 1987 began trying decayed wood chunks to fill orchid pots, achieving unexpectedly good results. Allorchidsgrown with it showed gratifying growth, with higher rates of sprouting and flowering, more leaves, glossy leaf color, and recovering plant height, nearly approaching the robust level of wild plants. Research has found that decayed wood not only has the common advantages of other media, but can also achieve the effects of foreign soilless cultivation, better improving the limitations of growingorchidsin pots. ① It is itself rich in organic matter, and can also absorb, retain, and store fertilizer, which is beneficial to the growth of orchid symbiotic fungi, can supplement the insufficient soil fertility in the orchid pot, and can provide nutrients to orchids over a relatively long period. ② Its pH is acidic (4.5-7), so no acidification treatment is needed when using it. ③ It has excellent heat dissipation, heat preservation, and permeability, and is economical and easy to obtain, safe and reliable to use; whether in colder regions or hot regions, or in cities and rural areas, it is both cheap and a superior medium. Practice has proven that any kind of decayed wood works well, with willow and pine being especially good. When using it, it must be disinfected; either chemical disinfection or sun exposure disinfection will do. Generally, do not steam or bake it at high temperature, so as not to destroy its organic matter. When using decayed wood to fill pots, there is no need to repot every year; generally once every 3 years is suitable, as this helps orchid roots attach to the decayed wood and absorb nutrients from it. (Nanjing - Zhao Keshun)