Good medium for Vanilla planifolia?

[My Green Pets]

Hello,

I am volunteering at my local botanical garden to help specifically with their orchid collection. They have a huge Vanilla planifolia in a pot with god-knows-what kind of medium in there. I have been given the task of repotting it...but I want to do it right. Would standard orchid mix be ok, or is there anything special about Vanillas?

Thank you

 

[abax]

I've seen them grow quite well in Ball Seed potting mix
with extra large perlite for drainage.

 

[h_mossy]

I've seen mixtures of potting soil, composted manure, and bark or small pieces of tree fern or coconut husk instead of bark. I had one that was in a large pot, but after re-potting I noticed that the roots had not penetrated the mix, they grew very long in circles inside the pot and only at the very top layer of the medium. The professional growers typically gouge out a very shallow trench, cut a piece about 5 ft long, strip the leaves on that lower portion that will be in the trench, tie the upper portion to an upright pole or thin tree trunk, and very lightly cover the trench with very loose media similar to the mix I described. They then lightly spray the trench to keep it moist while the lower portion grows roots. As far as I could see, the roots just spread out on the surface, and never really penetrated the media in the area. Generally there are about 2 short roots per node, and once they find a favorable area, usually lightly damp, the roots will begin to elongate, and develop tiny root hairs to aid in the uptake of moisture and nutrients.