Name that Paph.. . hint: Slivraar glavc x phil

[Roberta]

Originally Posted by Optimist

Pen, I tend to think that the reason that it bloomed was hard water.

Just to add to that, the Huntington Botanical Gardens in southern California has one of the premier Paph collections, and those are watered with well water (high calcium, fairly high dissolved solids, relatively high pH from the calcium bicarbonate) They have the facilities to give each type of orchid whatever it wants, and Paphs love the hard water. Phrags want RO, but not the Paphs.

[pychou77]

Good to know that, and it does make sense as tap water contains minerals not present in rain water. I use rain water to avoid salt accumulation as often mentioned in books. However, I don't think commercial growers would use rain water either. Thank you both!

[Optimist]

Originally Posted by pychou77

Good to know that, and it does make sense as tap water contains minerals not present in rain water. I use rain water to avoid salt accumulation as often mentioned in books. However, I don't think commercial growers would use rain water either. Thank you both!

Actually, you might go farther into the analysis.
The Ogallala Aquifer (where my town gets its water) is a carbonate-rock aquifer, and Ohio gets its groundwater from alluvial-glacial sources.

My idea, in this case, would be to re-mineralize the water, perhaps use rock dust? Calcium-magnesium for aqua gardening? Etc?

Also, is the Salt "sodium chloride"? There are many kinds of salts, including calcium carbonate and magnesium.

[pychou77]

As calcium supplement for orchid, sprinkling some crushed egg shells into the pot is what I did. However, I noticed that most orchid roots like to cling onto lava rocks instead of the egg shell. I read somewhere that Ca in egg shell is not "released" easily. Sprinkling some crushed Centrum tablets onto your favorite orchids might not be a bad idea..

For those interested, below is a table of the mineral contents of some lava rocks. BTW, I believe some of the chemical formula, e.g., Na2O, are not the actual forms of those minerals in the rock. I wish the phosphorus level could be higher for better flowering (?).

[estación seca]

Even those Paphs seeming to grow on rocks mostly grow on a layer of decaying leaf mold on the rocks. Microorganisms in the leaf mold may be able to dissolve rock with acids they produce, in order to make rock minerals more available, which makes any excess more available to the plants.

Egg shells contain calcium tightly bound in protein complexes. They evolved to be almost impervious to bacterial and fungal attack. The calcium is only released when the calcium-binding protein is metabolized by soil microorganisms. The fact that chips of egg shell can last for many years in moist potting soil shows this hardly occurs at all. I believe egg shells provide next to no supplemental calcium when used in potting mixes, despite what people have been doing for hundreds of years.

Calcium solubility in water is strongly affected by pH of the water. You will get a bigger bank for your buck by adjusting the pH of your calcium-containing water to the range 6-7, rather than adding more calcium.

Most plants actively block calcium uptake through the roots, except at the collar just behind the root tip. Excess calcium leads to minerals precipitating inside the plant. Teleologically one can think of it as a mechanism for taking up calcium only when the plant is in active growth. I don't know whether this is true about orchid roots.

[Optimist]

Here is an interesting article, Planting in rocks, roots constantly wet, high mineral calcium (limestone) similar to what I was doing (it seems). https://staugorchidsociety.org/PDF/2...inLavaRock.pdf

Read this and tell me if you think powdered dolomite lime might be good to use.