Re: In-ground Planting Mix

Dear all,

    I agree with Lynn. What is true for epiphytes may not be true for 
geophytes. I mean, in places like Central Brazil, the higher the pH of the 
soil, higher the diversity of Aroids. In fact, I am suspicious that the 
problem is not the pH itself, but the availability of calcium. Limestone 
outcrops or limestone-derived soils are much richer in aroids than 
surrounding areas. Many Amorphophallus species are endemic to limestone 
outcrops (am I correct, Wilbert), as well as some tuberous Xanthosoma, 
Taccarum, Spathicarpa, etc. In pure forms of the Brazilian cerrado 
vegetation, that is known as having the soil poor in calcium, no aroid is 
known to occur. However, limestone outcrops in surrounding areas that are 
usually in drier conditions may support a diverse aroid flora. Correct me if 
I am wrong, but even in rainforests growing in sandy soils are high in 
calcium that is held in the biomass and in the fast recycled humus. If you 
have ever worked with the anatomy of aroids, you will note that there are so 
many calcium oxalate cristal in almost every tissue that they must have come 
from somewhere!!!

                                Very best wishes,

                                         Eduardo.



>joe---
>
>i've never tested the ph in the beds.  the acidification is a natural and
>expected process.  i think that it's not so much a matter of aroids
>preferring acidic conditions as matter of their NOT preferring alkaline
>conditions.  generally speaking. most of what we grow are epiphytes on 
>trees
>in their native habitats......but then there's anthurium reflexinervium 
>that
>grows on limestone rocks as do many of the alocasias!  so, i simply try to
>keep it 'even'.  most plants, not just aroids, generally prefer between 5.6
>and 6.6 ph and at that level, will properly absorb at least some
>nutrients....... if my poor memory serves.  the old, tried and true Selby
>epiphyte mix includes lime.
>
>lynn
>
> > lynn, at what ph does one add lime?  It has been my experience that most
> > aroids prefere acid.  The ph would be most helpful to all.  Joe
>
>

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