PH Inquiry, use of limestone screenings for paphs & phrags

[Kawarthapine]

I usually add a combination of oyster shell and silica sand to tweak the ph and help improve leaf vigor amongst my paphs and phrags.

I'm out of my homemade mix and Paph Magic and wonder if anyone has tried adding simple landscaping grade, limestone screenings. Note: My mix typically includes spagnum moss, coconut husk, charcoal and sponge rock/perlite. I don't let my plants sit in water unless I am away and replace medium every 12-18 months.

I have found lots of local, terrestrial orchids growing on and near limestone, but am not sure about application rates for the crushed, commercial variety.

Can anyone offer feedback, endorsements, cautionary notes, etc...

Many thanks!


Kawarthapine

 

[eteson]

I think that dolomite powder works much better... not sure if you can get it there but if you can, try it... one tsp/month on top of your mix.

 

[John M]

If I am concerned about the pH of a mix being too low, I add limestone screenings to the mix. Plants do fine in it.

BTW: This thread is in the photo section. Could an admin move it to "Slipper Orchid Culture", please?