Paph spicerianum
 

Howdy all,

I grow a dozen or so paph species from small to large. All receive the same medium and care, though I use a coarser mix for sanderianum and victoria-mariae than the others

Everything is green, growing and flowering well, except for my spicerianums. They are strongly chlorotic though I still get some smallish flowers.

I'm guessing that there's some sort of nutrient deficiency though I don't know for sure since my other paphs are doing great(-ish) Does spicerianum have any particular needs that I'm missing? Thanks! Steve Herje

How are you fertilizing? What product, what numbers, what concentration do you you use, how often, and do you know the mineral content of your water?

Spicerianum is one of the few paphs in my collection that thrives on a drafty windowsill-- most of the others are happier in the warm grow tent. I grow in the Northeast, FYI.

Spiceranum and Fairianum both have a fairly dry and cool winter in their native environments compared to other paphs based on a quick review of my paph Baker sheets.

Another note in the Baker sheet - this species grows on limestome cliffs. It may need extra calcium. Many people use a top dressing of dolomite lime on Paphs from this type of environment. Also, there is a note that it grows in areas where there is plenty of water, from dew and mists even when there is no rain. I would certainly not reduce water.

Paph spicerianum
 

Howdy again all,

What would we do without these forums (fora?) (We'd have more viable orchid societies I suppose.)

Seriously, thank you all for your input.

Here goes: I have well water which includes the following relevant parameters

7.5 pH
Alkalinity CaCO3 210
Nitrate 50 ppm
Calcium 90 ppm
Magnesium 45 ppm
Soluble sulfate 37 ppm

Other trace elements necessary for plant nutrition are at about zero ppm.

Plants are mostly potted in terra cotta with a mix of 50% medium Orchiata (could they possibly have come up with stupider size designations?) 25% #3 perlite and 25% forest moss. A couple larger plants have larger bark added.

Plants are either sitting on the ground in a greenhouse with nighttime lows around 40F in the winter or in the basement on shelves under metal halide lights with nighttime winter lows around 55F. All species but two generally spend winters in the greenhouse. I did find that sanderianum and primulinum hated the cold with sanderianum showing actual damage. Both were returned to the basement. Selection of cold loving paphs was based on information contained in Birk, Nash or Davis.

Plants are watered with tap water or RODI/rain water, with the greenhouse plants more likely to get well water.

In addition to nitrogen already in the water plants are given a small dose of Florikan (Nutricote) 12-4-11 cal/mag plus minors 180 days annually which helps supplement nitrogen among other things. Those plants which are in areas that tend to be watered with RODI water are given small amounts of MSU to help compensate for the nitrogen already present in my well water. All my orchids are regularly given Kelp-Max.

Because I have hundred of plants in many different families I use widely different fertilizers. But I try to be consistent with fertilizing my orchids. In addition to the above, my paphs are sometimes given dilute calcium nitrate. I'll also sometimes give the orchids, including paphs, a pinch of Epsom salt or chelated trace elements.

Which brings me to my original question. Why, among 25 paphs consisting of at least a dozen species, are the two spicerianums are the only ones that are chlorotic. All the rest are deep green and healthy under nearly identical nutritional and environmental conditions. Speculation is fine.

Thanks again. Steve Herje, SW WI USDA zone 3