Maybe I should have asked my questions differently.
I see questions posed on a regular basis, asking about the need for “supplemental” calcium in the normal culture of paphiopedilums. Many paph growers seem to agree on the requirement. A somewhat related, but unasked question is that of pH requirements.
Based on my own personal observations in different Paphiopedilum habitats, I began to question the often-repeated idea of the need for calcium. My first clue was in the Gulf of Siam when I found P. godefroyae growing both on limestone rocks and on trees, each within feet of each other. Other locations showed similar conditions. The fact there is no limestone, or calcium on tree limbs raises the obvious question.
Another observation, that those paph roots are always embedded in acidic mosses, and yet are also attached by root hairs to alkaline limestone, has never been determined with a reasonable degree of certainty as to which is more important, if either. I believe it is the mosses which support the Mycorrhizae necessary for the growth of Paphiopedilum seeds after their germination, and wherever the mosses live, so will the paphiopedilums. To me, it is no more complicated than that.
For those who have read my new book, they will know that my questions about pH values and the fact that some orchids grow on rocks, were first aroused in 1971 when I observed the rupicolous laelias of Brazil. When those laelias began to be imported and grown here in the US, we had terrible luck trying to grow them dry, which is what we deduced were their conditions in habitat: ‘rupicolous’ = rock-inhabiting, or dry-growing. In reality, I found them growing with their roots firmly embedded in thick pads of persistently wet mosses, perched atop boulders of granite, or sometimes in trees.
From the beginning of my interest in them, I grew all but an experimental handful of my paphs with no calcium supplement, they simply got what came from our local water supply. In addition, after I developed my own potting mix, which incorporates fir bark, green moss and river sand, I stopped fertilizing, or perhaps I should say that I reduced it radically. Not surprisingly, my plants thrived. My collection contained every known paph species but 6 or 8, and many hybrids, as well as thousands of other kinds of orchids
There are a great many falsehoods circulated about orchid growing, a lot are centered on paphs. My own cultural experiences, and those of several friends from different areas, showed findings contrary to much of what was, and still is generally believed. This is why I continuously receive letters from people who have recently read my paph book, thanking me for showing them the way to successful orchid growing.
While I am confident in my own experiences, I have been out of orchid growing for many years and appreciate the possibility that I might have missed important information concerning good and hard scientific data about Paphiopedilum species and/or hybrids.
The knowledge that science is unable to show the actual REQUIREMENTS for such economic crops as barley, wheat, soybeans and even corn, compels me to ask my question. On the other hand, we have a number of knowledgeable orchid growers out there, some of whom may have done important work based on establishing plant requirements.
I appreciate your comments Bob Wellenstein, as do I your wife’s generous gift of the P. lynniae plants, which are doing very well in my new greenhouse. I also appreciate the enormous amount of work you have devoted to paphs, and to orchid growing, and I have visited your Web site on many occasions. While I do not agree with every one of your statements, I do appreciate they are based on your own personal, and obviously well documented and diligently observed experiences.
We each live in different parts of the US, and each grow under different conditions, so there will be different results from our separate conditions. I respect your observations as you do mine, even while some are contradictory. It is obvious that plants can be successfully grown under many different conditions and that there is no single ‘right’ way. I came to the opinion long ago that orchids will grow in just about any potting media, so long as their growing conditions are adequate and are properly controlled.
I know there are other curious orchid growers out there and I am hoping to also hear from them. My question about hybrids perhaps should have asked about “experiences” with using calcium supplements rather than about “requirements.”