Hi Julie,

Thanks for yet another great article. Anyway, you didn't say what the best orchid pH should be. Is it between 6.5-7.5????

To try and answer Tmai's question (though not totally) pure water has an equal amount of Hydrogen ions (the ions that make stuff acidic) and hydroxide ions (the ions that make stuff basic). So, once fertilizers start getting added, like Uncasteeb mentioned, the pH can go wild real easy. It will probably go up or down. It all depends on the pH of your fertilizer. If you are adding a fertilizer with a pH of 8 to pure water, then the overall pH will be 8(I think). And vise versa.
Hope I helped!