# Which paphs need calcium, and how much does each species need?



## Lance Birk (Mar 7, 2007)

I'm curious to learn the correct amounts to be supplied for each species of Paphiopedilum, and whether plant size or root mass makes any difference in the amount or concentration.

I also would like to learn which paph hybrids need supplemental calcium, as well as the amounts and concentrations.


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## Bob Wellenstein (Mar 7, 2007)

I do not know what exactly you are fishing for here, Lance, but I would hope as author of a Paph culture book you would know that all Paphs need calcium. We find the needs seem to be well met if the level is about 30 - 35% of the nitrogen level being supplied on a weight/weight basis.


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## NYEric (Mar 7, 2007)

Uh oh!


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## Candace (Mar 7, 2007)

Does MSU provide enough or is supplemental Calcium needed? Shhh. Don't tell my plants if it is, as they've never gotten it.


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## gonewild (Mar 7, 2007)

Candace said:


> Does MSU provide enough or is supplemental Calcium needed? Shhh. Don't tell my plants if it is, as they've never gotten it.



MSU, in theory should provide enough. Just tell your plants it does.


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## Bob Wellenstein (Mar 7, 2007)

Hi Candace. There seems to be some variations on these "MSU" formulations. The plug special I use as the primary fertilizer has 6% Calcium and 3% Magnesium and it seems adequate on the Calcium levels without supplementation. I do like to supplement Magnesium periodically for all and even heavier for Paph rothschildianum. My guess is 75% of the folks reading this forum would see a positive difference in their plants within 2 weeks if they gave an Epsom Salt feed ( 1-2 teaspoons per gallon) to their plants next watering.


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## gonewild (Mar 7, 2007)

Bob Wellenstein said:


> Hi Candace. There seems to be some variations on these "MSU" formulations. The plug special I use as the primary fertilizer has 6% Calcium and 3% Magnesium and it seems adequate on the Calcium levels without supplementation. I do like to supplement Magnesium periodically for all and even heavier for Paph rothschildianum. My guess is 75% of the folks reading this forum would see a positive difference in their plants within 2 weeks if they gave an Epsom Salt feed ( 1-2 teaspoons per gallon) to their plants next watering.



Bob can you elaborate on that a little?
How often do you feed the extra Magnesium?
Would it not be better to increase the amount of Magnesium ratio given with the fertilizer solution as a constant feed?
Are you suggesting this application for all orchids or are you only talking about paphs?


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## Bob Wellenstein (Mar 7, 2007)

I will limit my comments to Paphs and Phrags just because they are where 95% of our experience lies. I work with concentrates and cannot push the Magnesium up any further without precipitates, so pulse the Magnesium, ideally every two months.


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## gonewild (Mar 7, 2007)

Bob Wellenstein said:


> I will limit my comments to Paphs and Phrags just because they are where 95% of our experience lies. I work with concentrates and cannot push the Magnesium up any further without precipitates, so pulse the Magnesium, ideally every two months.




Thanks.
Ideally what would you like the ratio of Magnesium to Calcium to be in the irrigation water. Assuming you did not work with concentrates and were not worried about precipitates in your stock solution?


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## Eric Muehlbauer (Mar 7, 2007)

Bob- can the epsom salts be combined with fertilizer, or should it just be given as a drench on its own? Right now, I keep epsom salts isolated from any other ingredients, as a drench in between normal fertilizing...not as often as you suggest though...I keep forgetting. Take care, Eric


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## Rick (Mar 7, 2007)

Lance Birk said:


> I'm curious to learn the correct amounts to be supplied for each species of Paphiopedilum, and whether plant size or root mass makes any difference in the amount or concentration.
> 
> I also would like to learn which paph hybrids need supplemental calcium, as well as the amounts and concentrations.



This question may be linked as to whether calciolus speceis have different Ca requirements than non-calcereous species.

IMHO the calcium requirement is not different from one species to the next, but the overall pH environment will differ between calcarious and non-calcereous species. This can make a pretty big difference to the plants in bioavailability of various nutrients and their abilty to uptake nutrients and trace elements.


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## IdahoOrchid (Mar 7, 2007)

Back to one of Lance's original questions:



Lance Birk said:


> I also would like to learn which paph hybrids need supplemental calcium, as well as the amounts and concentrations.



Check out this site for WHICH paphs are calcium hogs:

http://ladyslipper.com/calsub.htm


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## Heather (Mar 8, 2007)

IdahoOrchid said:


> Back to one of Lance's original questions:
> 
> 
> 
> ...



Yes, well, seeing as that is Bob W's site...I admit, I too am a bit surprised with Lance's question in the first place. Since he wrote the Paph. Grower's Manual and all.... Not sure why you are asking here, Lance...not discouraging, it's a great question, but...don't you already know the answer to that?


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## Bob Wellenstein (Mar 8, 2007)

I did not address supplemental Calcium because, as has been on our website for 10 years now, we, based on experience and expreimentation, believe that it is a pH issue, not an increased calcium need. We adopted and suggest the use of the crushed oyster shell because it is a self correcting system, the oyster shell dissolves in proportion to the acidity of the irrigation water. The need results from the difference between different Paphs, some doing best with somewhat acidic conditions as opposed to those that appear to have adapted to more alkaline conditions, being grown in a mixed collection. The easiest method for us is to irrigate with the slightly acid solution, and top dress with the oyster shell. The chart in our website is based on our experience, not second hand references to habitat in books. I do not mean to question Lance's wisdom, he just has a history of asking questions on forums in a cryptic way that does not make sense to many of us. At one point he had taken a photo of an unusual Paph. lowii from our website, clearly labeled with our nursery name, and posted in on OSF and asked who had this plant?? We were thrilled with Lance's first book oh so many years ago, and he was kind enough to send us a complimentary copy of his latest. In honesty I am disappointed with it, but still will respect Lance as a pioneer in Paph growing. Lynn was thrilled to be able to send him some plants of Paph lynniae (the real thing) he wanted to grow. We need to remember everything we know has been built on the foundation laid by people like Lance, just as his was by those before him. I may disagree, but I have respect.


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## IdahoOrchid (Mar 8, 2007)

At work I sometimes as the operators questions that I already know the answer to or at least have a pretty good idea what the answer should be. I call them probing questions and use them to see if any further assistance is required and to help them. It gives me a feel for the knowledge base of the work force and lets me know what additional training is required.

Is that what Lance's question is?


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## Lance Birk (Mar 9, 2007)

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.”


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## Leo Schordje (Mar 9, 2007)

Lance & Bob, 
Thank you ! This discussion is invaluable. It is a sharp reminder to me of how many of the things I do are based on myth rather than science. I need to spend some time and really look at what I do and separate science from alchemy. Thanks
Leo


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## SlipperFan (Mar 9, 2007)

Exceedingly interesting discussion. In my relatively short time with orchids, I have observed some of the things Lance said. Different regions/growing conditions mean that what works for one person may not work for another. I'm not very scientific in my approach to growing orchids, but I do experiment quite a lot and see what works for me. I'm still learning...


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## terrestrial_man (Mar 17, 2007)

would egg shells added to the mix make any difference?


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## IdahoOrchid (Mar 17, 2007)

I have heard of people doing that. I would make sure you soak and rinse them like you would oyster to get all of the residual egg whites off of them first.


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## gonewild (Mar 17, 2007)

Egg shells would dissolve so fast in the mix their benefit would be too short lived. The idea of top dressing is so you can see when the material is gone and add more.


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## DavidH (Mar 20, 2007)

I use an MSU based fertilizer for the west coast developed jointly by Fred Clarke of Sunset Valley Orchids and the folks at MSU. After reading Bob's article on supplemental calcium, I put crushed oyster shell from a local feed store on half my armeniacums and micranthums and left the other half without (approx 30 plants with, 30 plants without). After 6 months, the majority of plants with oyster shell dressing had 1-3 stolens growing up through the oyster shell whereas I had almost no stolen growth on the plants without. It's possible to argue that the oyster shell top dressing kept the potting media more moist versus adding any additional calcium.

The fertilizer rate I use is measured at 50 ppm Nitrogen with an EC of 0.39, and PPM of around 280-300 using RO water at 17 ppm. PH runs around 6.4 (summer) - 7.0 (winter). I've noticed the local water supply PH is higher in the winter months versus the summer months (7.4 summer, 8.0 winter).

Based on my personal experience, I plan on adding oyster shell top dressing to the majority of my paphs. As Bob mentioned, it can't really hurt. After reading his articles, I've also recently started adding supplemental epsom salts, with no other additives, when watering.

The bottom line with all orchid growing is that while all plants have basic requirements, each person has unique growing conditions that may result in slight to significant differences in potting media, fertilization rates (within a narrow margin), watering schedule, etc. 

Personally, I like experimenting. After all, plants die...get over it. 

-Dave
p.s. and if get get over 30% of my armeniacums and micranthums to bloom next year, I'm going to throw a party!!!


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## gonewild (Mar 20, 2007)

DavidH said:


> I use an MSU based fertilizer for the west coast developed jointly by Fred Clarke of Sunset Valley Orchids and the folks at MSU.



How is this MSU formula different from others?
What is the NPK ratio?
% of Ca and Mg?
Who sells it?



> After reading Bob's article on supplemental calcium, I put crushed oyster shell from a local feed store on half my armeniacums and micranthums and left the other half without (approx 30 plants with, 30 plants without). After 6 months, the majority of plants with oyster shell dressing had 1-3 stolens growing up through the oyster shell whereas I had almost no stolen growth on the plants without. It's possible to argue that the oyster shell top dressing kept the potting media more moist versus adding any additional calcium.



Great experiment. 
What type of media are the plants growing in?
How often do you water?



> The fertilizer rate I use is measured at 50 ppm Nitrogen with an EC of 0.39, and PPM of around 280-300 using RO water at 17 ppm. PH runs around 6.4 (summer) - 7.0 (winter). I've noticed the local water supply PH is higher in the winter months versus the summer months (7.4 summer, 8.0 winter).



How often do you apply fertilizer?


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## gonewild (Mar 20, 2007)

Last week I gave our plants an extra dose of Epsom salts based on Bob's recommendation to see what happens. The first of next month we'll see if it made a difference. :drool:


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## ScottMcC (Mar 20, 2007)

this discussion has me wondering about water hardness. after all, calcium and magnesium are the two main culprits in making water hard, and many orchid growers use ro water. so...if you were to just use tap water, would you still need supplemental calcium?


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## gonewild (Mar 20, 2007)

ScottMcC said:


> this discussion has me wondering about water hardness. after all, calcium and magnesium are the two main culprits in making water hard, and many orchid growers use ro water. so...if you were to just use tap water, would you still need supplemental calcium?



That would of course depend on how much calcium your water contains.


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## IdahoOrchid (Mar 20, 2007)

gonewild said:


> That would of course depend on how much calcium your water contains.


Would it not depend on what form it is in as well?


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## DavidH (Mar 21, 2007)

> How is this MSU formula different from others?
> What is the NPK ratio?
> % of Ca and Mg? Who sells it?



Good question. The info on the bag has rubbed off, but I have a new 50 lb bag on order and should arrive later this week so I can answer this question. Or, call Fred and he can answer since he developed it with the MSU folks. Also, a correction...the correct EC number is .40 not .39



> great experiment.
> What type of media are the plants growing in?
> How often do you water?



The plants are growing in either a pumice/coir/perlite mix, or Aussie Gold mix, but I'm switching everything over to Antec's CHC mix due to the Aussie mix staying a little too wet and not enough airflow into the roots. I water 1-2 times a week in winter, 3-4 times a week in summer.



> How often do you apply fertilizer?



It used to be every watering. However in the last two months it was every other watering due to a new tank and water pump installation. I'm switching back to every watering once I redesign my injection system due to the new pump and water tank I now have.


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## gonewild (Mar 21, 2007)

IdahoOrchid said:


> Would it not depend on what form it is in as well?



Yes and no. It really depends on a lot of elements in the water. Most water does not have enough calcium to supply the plants with all they need. 
To really know for sure you need to see a water analysis and interpret the total balance of all the minerals it contains.

A problem with using a water source high in calcium and magnesium will be that it is likely also high in total salts (PPM, TDS). When your water is already high in salts it makes it difficult to add enough "fertilizer" elements to your irrigation water without the total salt concentration getting to high for the health of the plants.

The big benefit with RO water is you don't need a water analysis to determine what nutrients you should add. You know you need to add everything the plant requires. And it is easy to determine what to add.


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## Bob Wellenstein (Mar 21, 2007)

Many areas of the US have more than enough Calcium in the tap water to meet the needs of Paphs (and please remember that the point of top dressing certain species is likely pH control, not need for extra Calcium). I do not believe you will find sufficient Magnesium to be as widespread. Calcium in the water supply is generally from Calcium Carbonate, insoluble in pure water but soluble in the presence of acid resulting in Calcium and bicarbonate ions in the water. The problem is, when the water is removed by the plants or via evaporation, the excess precipitates out as insoluble Calcium Carbonate. When you use water free of Calcium Carbonate such as rain water or RO water, and add the appropriate amount of Calcium in a highly soluble form such as nitrate, any that precipitates out will be very effectively flushed with the next watering. This and a lot more is explained in the various articles at http://ladyslipper.com . They were written almost ten years ago, updated as new information is needed for clarification, to save the time from repeatedly trying to answer these questions.


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## Bob Wellenstein (Mar 21, 2007)

Sorry if that sounds grumpy, but I am this morning!


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## Bob Wellenstein (Mar 21, 2007)

When I used to go out and give talks I can't tell you the number of times I would have people come up and say "I have heard brachys are hard to grow, but I do great with them, but I can't grow Maudiae types". I would talk to these folks and inevitably they had hard water. The opposite was also true, folks who did great with not only Maudiaes but mastersianum and similar species, but couldn't keep a bellatulum alive for more than a year, and they almost always either used rain water or had naturally pure water sources. Aside from just Paphs, it also became obvious that if you found an excellent orchid grower who didn't seem to have a clue as to why they did so well, you had found someone with naturally excellent water. Water, with whatever is needed in the form of minerals for the plant, and in the form of good humidity, seem to be one very important key in what separates growing Paphs from growing really healthy, happy Paphs.


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## gonewild (Mar 21, 2007)

There is a maximum desirable calcium level. At high levels calcium will interfere with the uptake of other nutrients. This is especially true of the micro nutrients. Adding calcium to raise the pH may be good for plants that naturally need a high pH but it also may inhibit the growth of those plants that don't.

To much empathies is being put on isolated parts of the nutrient requirements of plants. Adding excess of one nutrient can and will cause a deficiency of another and vice versa. The ratio balance between nutrients is very important. That is why MSU formulas work so well, they are based on the balance of the whole contents.


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## Rick (Mar 24, 2007)

gonewild said:


> There is a maximum desirable calcium level. At high levels calcium will interfere with the uptake of other nutrients. This is especially true of the micro nutrients. Adding calcium to raise the pH may be good for plants that naturally need a high pH but it also may inhibit the growth of those plants that don't.
> 
> To much empathies is being put on isolated parts of the nutrient requirements of plants. Adding excess of one nutrient can and will cause a deficiency of another and vice versa. The ratio balance between nutrients is very important. That is why MSU formulas work so well, they are based on the balance of the whole contents.



Calcium does not raise pH. The alkalinity from calcium salts such as Lime (calcium hydoxide) or the calcium carbonate in oyster shell will raise pH, but calcium chloride, sulfate, or nitrate. are pH neutral salts.


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## IdahoOrchid (Mar 24, 2007)

Can anyone tell me about Dical and Calcite? I have access to these at work.


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## gonewild (Mar 24, 2007)

IdahoOrchid said:


> Can anyone tell me about Dical and Calcite? I have access to these at work.



I think both are pretty much insoluble in water and would not be much good for your plants. Dical is very high in phosphorous and would throw nutrient balances off.

What are they used for in your work?


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