When choosing a mix for repotting an orchid, one can either select a mix based upon the type of orchid or by the root size. If all else fails and you don't know what type of orchid it is, the root size is enough to choose a suitable media. Orchid mixes refer to fine rooted orchids and thick rooted orchids, but what exactly is meant by that?
In this pictorial we use a standard #2 pencil as a guideline. Both orchids are mounted so their roots are clearly visible.
Fine Rooted Orchids:
This mounted Oncidium Gower Ramsey is an example of a fine, or thin, rooted orchid. This division of an older orchid was mounted one year ago. This Oncidium is mounted on a tree fern mount which fine rooted orchids really love.
When potted, thin rooted orchids prefer small particle sized mixes such as our Oncidium Mix.
Thick Rooted Orchids:
This mounted Phalaenopsis is an example of a thick rooted orchid. Because it is mounted many of the roots are completely flat against the tree bark. We have found that most thick rooted orchids like cork or wood mounts. This particular Phalaenopsis is growing in the nook of a branch from a tree that was trimmed. This Phalaenopsis was also mounted a little over a year ago and now is in triple spike and seems very happy with its mount.
When potted, thick rooted orchids prefer medium particle sized mixes such as our Phal Dark Imperial Orchid Mix.