I used to import a lot of Chinese cymbidiums, and in discussions with the producer in Taiwan, I found they were growing them in a very open mix of tree fern chunks and pumice, and fed and watered them daily (sour milk as the fertilizer - yecch).
Figuring that sounded a great deal like semi-hydroponics, I decided to try that. Now all of my cymbs are grown that way, and they love it!
Des - when preparing CHC, try adding some calcium nitrate and/or Epsom Salts (magnesium sulfate) to the soak water. I use about a tablespoon of each per gallon. It's use is derived from water softeners:
Most water "softeners" expose incoming water to a brine (NaCl) solution. Sodium chloride will dissolve more readily in water than will the calcium- magnesium, and iron minerals (mostly carbonates) that are the most common minerals in "hard" water, so they precipitate out, leaving the sodium in the water. Orchids do not like high-sodium water, so we all recommend that folks don't used it. So now let's shift our thinking to media preparation.
In that case the sodium is already in the medium, and we want to get rid of it. If we expose the CHC to a solution full of calcium and magnesium ions, that same solubility imbalance is there, but this time we extract the NaCl from the chips into the solution, replacing it with CaNO3 and MgSO4 (good plant nutrients). Then we dump the liquid, and the majority of the sodium chloride goes with it.
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