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How important is lime

I have been delaying purchasing some of the more "difficult" Paphiopedilum species due to their supposed dependency upon alkalinity in the soil. Basically a PH up to neutral 7, but even that is far more alkaline than peat or even LFS. Some things I've read include going so far as to use crushed limestone cement pieces in the soil mix.

Is anyone growing P. rothschildianum, P. sanderianum, etc. who are said to "require" this soil ammendment? Is it not as important in cultivation as natural distribution? As in the case of Nepenthes northiana, who does just fine in a normal Nepenthes mix but is said to be a limestone specialist in the wild...

If limestone is required for proper care of P. roth and P. sander, how are you supplying the lime and how often?

Thanks for any thoughts!
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Hi swords,
We use carbon filtered tap water on the Paphs, and occasionally RO to flush the pots. Our water is loaded with calcium carbonate, and is a natural for the species you mentioned and brachys like belatulum and niveum.
The northianas are treated like all the Neps, RO or collected rain water. We grow them in regular mix. Still, they are really touchy.
Our problem in Florida is getting low night temps to induce flowering in rothschildianum. If you get conditions halfway to their liking they just grow and never flower.

Trent
 
Thanks Trent,
My N. northiana has always grow very well with thick sturdy leaves and nice pitchers on each leaf  but slow to increase in diameter. It has now started to actually spread and is about 35-40 cm in diameter. I have read that an occasional flush with limewater might  be benfitial to it but I'm afraid to try anything due to it's touchy reputation. Do you do this for N. northiana? In what ratios?
Mine grows in plain long fibered sphagnum moss, much of which is alive and growing nowadays. There also maybe a bit of orchid bark in the soil, I don't recall anymore.

Wow, only use R/O to flush paphs occasionally? I use R/O for all my plants and fishtanks for fear of my tap water's low PH but very high karbonate hardness (salinity) due to the sodium filter the condominium water system uses. Is there a product I can add to the R/O water (like horticultural lime or Kalkwasser calcium carbonate supplement for reef tank aquariums) to harden up the R/O for the more "hard water" species?
 
I hear that the Paph growers in Hawii use Cal-Mag because their water is collected rainwater. I've never used Cal-Mag because we don't need it down here, and it's hard to find in south Florida. Our problem with calcium is there's too much of it! I hear they use it on Vandas too, and in fact Vandas actually get a disease as a result of calcium/magnesium deficiencies. We grow Vandas and Ascocendas too and never have had problems because of our high ph values.
As for the northiana, we use strictly RO on them. they grow slowly and sometimes pitcher, but cannot figure out what else to do for them. I would be afraid to put calcium on them for fear of shock, but maybe they need it.

Trent
 
Calcium deficiency is quite dramatic. Constant use of RO/distilled/rain water without supplimental feeding would certainly be an issue.

Deffinately don't use any water run through a sodium water softener. That will kill most plants in short order.

I wouldn't bother with hardening water for Nepenthes and if they are regularly fed with insects then mineral defficiency should not be an issue. A good fertilizer for houseplants and orchids and such would be needed however. Cal mag is good stuff but there are also a bunch of other fertilizers available for soilless (peat based soil) or hydroponic growers that contain all macro, minor and trace elements.

On a side note.. most fertilizer found at the garden shop also contain minor elements like calcium but it is not usually listed on the label. If you read the ingredients however you might see something like calcium phosphate as the chief ingredient supplying phosphate. While supplying phosphate it is also supplying calcium.

Keep in mind that most fertilizer is designed to mix with regular water that contains significant carbonate hardness. This acts to buffer the fertilizer and keep the Ph within acceptable range. If you add fertilizer to pure water such as DI, RO, Rain, 9 times out of 10 you will drop the Ph of the solution down into the 4-5 range (or lower). This should be adjusted back up to 6-6.5 for your houseplants and orchids etc.

Tony
 
Bob Wellenstein from AnTec Labs wrote this awsome article on fertilizer and water and the relationship between the two. It is very technical but unavoidable when dealing with water/fertilizer chemistry.

At the bottom are also more links which talk more directly about mineral and calcium supplimentation for Brachys etc..
Notes on Fertilizer - Wellenstein

Tony
 
The Wellenstein's articles on Paph growing are top notch. He converted me to coconut husk chips, and use it with all Paphs and Phals now. I mix chips with aliflor and charcoal and have gotten great results.
Tony, you're a Lycaste grower? Some of the species bloom easily down here (s. Florida), while others need it cooler (such as the beautiful L. skinneri). Anyone hybridize the warm growers with coolgrowers to get something survivable in southeastern US?

Trent
 
There are a  few crosses using some of the Mexican species with some of the cooler growing ones.  Not alot though because they are so dominant for multiple generations that you can pretty much bank on yellow flowers somewhere inbetween in size.

I used to do alot of orchids, primarily Paphs, Lycaste, and Disa but have gotten somewhat away from it now with the CPs and the vast number of Nepenthes that only a short while ago I would never have dreamed of ever seeing in my collection!  Maybe one day I will get back into doing more.. still some of my awarded things floating around as Par O Bek ___

Tony
 
If you need to add magnesium, you can use a tablespoon of epsom salt in a gallon of water. Epsom salt is an old gardener's plant tonic and I've had orchid growers recommend it. I use it but not with every watering.
 
  • #10
Thanks Tony,
Perhaps my Gro More brand urea free orchid fertilizer (with all major elements and some minor) and the aquarium plant fertilizer (for all the minor & trace elements) is all I might need for the Paphs. and not have to worry about adding extra calcium. I was just under the impression I might have to do something exceptional for those species since I'd read about people using things like pieces of cement in their soil mix to add extra calcium.

How do I raise & stabilize the carbonate hardness of R/O water so that the water does not become too acidic? Do I simply add some baking soda-what porportions will be enough 1/2 tea spoon per gallon or...?

I feed my Neps every two weeks with crickets so I don't fertilize most of them anymore. But when the plants are only a few centimeters across I water with the balanced Gro More every 2-4 weeks until they create pitchers large enough to feed tiny 2 week old crickets.

EDIT: Thanks for that link, I love this kind of reading! I indeed know the "aquarium smell" of the ureates which they discuss in the article. I wish they had a chart for Gro More!
 
  • #11
I used to use potassium hydroxide solution to adjust pH.  You could use some calcium hydroxide to do the same.. Probably easier to get through the aquarium trade.  I would not use baking soda which is sodium bicarbonate.  In any event you should first test your pH after you mix up a batch of diluted fertilizer.  You might be lucky and find it is fine.

The use of a calcium component in potting mix, while adding some calcium which the plant needs, is more for neutralizing acidic potting mix.  I think in the case of some Paphs it has been shown to be helpful because it maintains the neutral to (in some cases) slightly alkaline root zone.  I know the Wellensteins use a crushed oyster shell in these instances.  They also use a balanced fertilizer with calcium and all other macro, minor and trace elements.  The fertilizer and the crushed shell serve different purposes to the plants health.

Tony
 
  • #12
Ah ha! You could be on to something here... crushed oyster shell! I like the sound of that!

I received a few huge bags of seashells a while back. After picking out all the specimen shells (and a few weird seeds!) I have many damaged and uninteresting shells that could be crushed up for such a purpose.

Is there something particular with oyster shells (I have plenty) or will any shell do?
 
  • #13
I would think any shell should do.  The crushed oyster shells are used in the poultry industry and a byproduct of the oyster (for eating) and pearl industry.

From my recollection, the shell pieces are flat and flake like but more importantly it is the easiest form of calcium carbonate to dissolve so it is more effective in adding minerals to the potting mix and buffering.  Sorry I don't recall the technical term but I think all shells, coral etc are the same form.  I would just be sure to soak them several times and rinse well to be sure all the sodium is gone.

Tony
 
  • #14
Thanks Tony,
I think I will go with the oyster shell method and see how that does. If I can buffer it "naturally" like this through erosion of shells and not relying on chemicals I would prefer to.

I picked up both volumes of The Genus Paphiopedilum by Guido Braem today at the orchid shop. The books look like they're geared towards cultivating the Paphs whereas the P. Cribb book looks more like the C. Clarke reference monographs. Have you seen these G. Braem books? I like that the book lists average year round temperatures, humidity, rainfall, light levels, etc. for each species' general area. As we know some of this info this translates to Nepenthes as well so it has a dual purpose!
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Speaking of Neps John deKanel came by the orchid shop today since he was in town showing some medical device at the Mayo Clinic!
 
  • #15
There is also crushed coral that you can buy at any aquarium shop. Its already pulverized. Its full of the tiniest little sea shells you've ever seen. I've bought some of this and think it might have a number of uses other than with the pings.
 
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