TDS for semi-hydro Zygo & Onc
 

So I just moved into a new apartment on the other side of town, which is great. But the tap there is a different source and is really bad - last year's water report was at 472 ppm TDS :shock: Needless to say, this has catalyzed me into schlepping 20L carboys of DI water from the lab (thankfully nearby) for watering the pleurothallids etc. and cutting tap water at least 50/50 for my traditionally-potted orchids that aren't super sensitive.

But I have only two orchids in SH, an Onc. ampliatum and a NOID Zygo, so back at the old place I'd just flush them thoroughly in the sink daily or every other day. If I were to continue this daily flushing with >400ppm TDS water, could I get away with that in semi-hydro? Since LECA has so much lower CEC than organics, would semi-daily flushing keep the cumulative TDS from creeping up? Does anyone have experience flushing with such ridiculously [TDS]? I tried searching this subforum but didn't come across any previous threads.

A sub-question, then, is how much TDS can an Oncidium sp. and a Zygo hybrid take happily? I want them to be happy, not just struggling. I guess if the answer is <400ppm then that's the answer right there.

Thanks for staying with me through this long post! Also sorry if this is the wrong section and I should be posting into alliance subforums.

hi there I am not orchid expert but I could said i have succese grow pal in semi hydro for a year . I have five mini pal that my friend give it to me. and all of theme are doing well and flower. I feed theme every day with 165 ppm . each I mix my nutrient is 1 quart ro water mix with botanicare cal/mag plus 40ppm ,dyna foliar grow 40ppm ,4 drop of gh flora micro, 5 drop of biobizz ALG . A. Mic (biobizz kelp). I spray my pal every morning at 7 am. 1 quart of mix enough for my 5 pal for a week.

The need for a particular water quality, as best I can tell from decades of growing, does not change from traditional culture to S/H.