Potting and Watering Guidance

[Roberta]

Originally Posted by WaterWitchin

Yep... 400 ppm is way better than mine. My pH runs about the same. And so far the only thing I must use R/O on are paphs, phrags, a psychopsis and a bulbo. I've heard must use R/O on Tolumnia, and just the opposite. Have gone both ways. Can't tell the difference.

You might reconsider for the Paphs, depending on what is causing your high TDS... at the Huntington Botanic Gardens in southern California, they use well water that ranges from 200-800 ppm (unpredictably, more often on the high side of the range) on their world-class Paph collection. In an article in Orchid Digest, Brandon Tam, their orchid specialist, states that they have tried it both ways and the Paphs actually do better with the well water than with RO. Now, the solids in their water are mostly calcium carbonate. If you had high sodium that would be a different story entirely.

Phrags, on the other hand, definitely do need good water.

[Ray]

Originally Posted by Stella1979

Thank you. I have looked into SH some. Would you say it has any benefits over self-watering using a closed reservoir and a wick?

Wicks work OK when applied to tightly-packed media like soil, where the capillary action of the fine crevices pull the moisture away from the wick, so it can "refill" and bring in more moisture.

In more "open" airy media like those used for orchids, the capillarity may happen within the individual particles, but is very poor between particles, so a wick will not have the capability of delivering water widely. With semi-hydroponics, the transfer is enhanced, as the "wick" - the LECA sitting in a reservoir - is so much larger.

[estación seca]

Tap water should have no or next to no nitrogen. You can look up your utility's water quality report online and find out how much calcium is in your water.

[Stella1979]

Well, again, I've yet to do the studying really required to fully understand water chemistry... but due to keeping sensitive aquaria, I have run multiple tests on my tap for nitrates, using different brands and what is considered quality test kits in the fish hobby... and I find that I have 40-50ppm nitrates in my tap water. So, while I can and will look at water quality reports, isn't it safe to assume that there is nitrogen content in the tap? I'm here to learn, so if my assumptions are wrong, please tell me.

And thank you, everyone, for sharing your thoughts and experiences!

[Ray]

The 2018 EPA standards for drinking water state that there should be a maximum of 10mg/L (ppm) nitrates.

[estación seca]

Contact your water utility. You should not have that much nitrate in your water.