Anne - I'm not sure ! I've never root pruned any of mine....just keep moving them up. Which one's do you have ?
I grow most of mine in a pretty chunky mix of Orchid Bark, Extra coarse perlite, Tree Fern fiber sometimes Coco husk chunks if I can find it easily and a little potting soil. If I'm growing them in a slate basket, I line the basket with Long fiber sphagnum moss first, then use the same mix.
Anthurium vittariifolium in the center, and Anthurium pseudospectablile upper left corner in slate baskets.
Anthurium verapazense, just before I moved it up to the clay pot. You can see some orchid bark and tree fern fiber in the mix.
