# A question about top dressing with dolomitic lime



## Carkin (Jun 12, 2015)

What do you do with crosses that mix calcicolous and noncalcicolous Paph's? For example Paph. Lynleigh in Pink (Ho Chi Minh x malipoense), would you use less dolomitic lime because of the delenatii in it? Or maybe none at all?


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## SlipperFan (Jun 12, 2015)

Good question -- I've wondered that myself. I've basically added oyster shell to all my Paphs that are mixtures, as well as the calcicolous ones, at about half the amount.


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## Ozpaph (Jun 13, 2015)

Me, too, Dot. Not sure if its the best but seems OK.


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## Stone (Jun 13, 2015)

Carkin said:


> What do you do with crosses that mix calcicolous and noncalcicolous Paph's? For example Paph. Lynleigh in Pink (Ho Chi Minh x malipoense), would you use less dolomitic lime because of the delenatii in it? Or maybe none at all?



Do you mean top dressing with powder or larger pieces? I think anything over 0.5mm does almost nothing.
I'm adding a very small pinch of limestone powder every 4 months or so (for pH control not for calcium) and spraying it with water until it disappears under the bark on all species but maybe a bit less on the non limestone types. I would treat your cross the same as malipoense but if you didn't grow hybrids you wouldn't have that problem. :evil:


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## Carkin (Jun 13, 2015)

SlipperFan said:


> Good question -- I've wondered that myself. I've basically added oyster shell to all my Paphs that are mixtures, as well as the calcicolous ones, at about half the amount.




Thank you, I'm glad to find out what you do.


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## Carkin (Jun 13, 2015)

Ozpaph said:


> Me, too, Dot. Not sure if its the best but seems OK.




Glad to hear that you do the same!


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## Carkin (Jun 13, 2015)

Stone said:


> Do you mean top dressing with powder or larger pieces? I think anything over 0.5mm does almost nothing.
> I'm adding a very small pinch of limestone powder every 4 months or so (for pH control not for calcium) and spraying it with water until it disappears under the bark on all species but maybe a bit less on the non limestone types. I would treat your cross the same as malipoense but if you didn't grow hybrids you wouldn't have that problem. :evil:




Lol, I know...I love species but I love hybrids too!!! 

I top dress with powder. I've been using about a quarter teaspoon in the spring and fall. For the crosses I've given preference to the pod parent or based on the leaves tried to determine which species is more dominant. I'm not sure if I'm on the right track or not.
Thanks for sharing what you do!


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## Justin (Jun 13, 2015)

what is your water source? depending on what your water quality is you may not need to use dolomite. my city water has lots of calcium in it already.


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## Carkin (Jun 13, 2015)

Justin said:


> what is your water source? depending on what your water quality is you may not need to use dolomite. my city water has lots of calcium in it already.




I use R/O water mixed with about ten percent well water.


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## Happypaphy7 (Jun 15, 2015)

I have a bunch of such hybrids ( delenatii x other parvi) and ones with no delenatii in them. 
I do not add any dolomite, lime stone, or sea shells to the mix. 
I use pretty much the same stuff for any orchids, and they are either coconut husk chip or bark chip mixed in with inorganic mix like lava rock or hydroton balls. 
I water with tap water which is low in mineral contents, to which a little bit of fertilizer ( with trace elements) might be added every so often. 

I believe the practice of adding oyster shell or lime stone to the mix came from the idea that certain plants may grow better since they grow on or near lime stone in their habitat. 
I do not think adding these materials help or hurt the plants. 
Adding certain dolomite product that dissolves too fast might even harm the plants.


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## Rick (Jun 15, 2015)

I stopped using dolomite, oystershell, or aragonite a couple of years ago, and replaced any potting mix system with new mix that was absent for these materials.

I also add back 10% well water to my daily watering/feeding regime. As per Justin's observations, most surface and ground waters will have more than enough Ca (and Mg).

I've measured the hardness, calcium, and magnesium concentrations that comes in from the well water and fert, so I know there is more than enough Ca and Mg in my water to exclude adding any more solids into the mix. 

If you are after pH control then that's' another matter altogether. Need to watch alkalinity (bicarbonates) not calcium for efficient buffering of acids. 

Your well water probably also has plenty of bicarbonate alkalinity to counter pH drop as long as excess N isn't getting into the system and you are just feeding bacteria. It's amazing how much pH drop problem is eliminated when you cut back on large episodic feedings (i.e the "weakly weekly" approach) and just trickle in tiny amounts on a daily basis.


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## Carkin (Jun 17, 2015)

Very interesting info, thank you!!


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