Mounting orchids
We highly recommend mounting orchids, as that’s how most of them grow in nature! However, if growing indoors, or growing in hot greenhouse/outdoor conditions, it may be better to pot some orchids. Indoors, we highly suggest that you pot all orchids and refrain from growing orchids that can only grow mounted (like the upside-down growing Encyclia citrina).
What you mount orchids on is particularly important when growing species orchids, but less so when growing hybrids. Typically, a cork or plastic mount is most commonly used. Because tree fern slabs are so expensive (and to date, still unsustainably produced), they are typically reserved for a grower’s prized plants. Tree fern slabs accommodate nearly every orchid type, and to some growers, yield even higher results than cork mounts because there’s more organic matter available for the orchid to absorb, a slight water absorption source (tree fern is slightly absorptive), and porous, allowing the airflow that many orchids love. Cork and polypropylene fabric are inert, so any moisture retention, pH influence, nutrient store is all up to the rest of the mounting media.
Sphagnum is the most common and universal substrate with which to mount orchids. Sphagnum is typically either loosely (for wetter and more humid environments) or tightly packed around the roots (in drier environments) to help the orchid have a small reservoir of water after being watered. Sphagnum should not be packed too tightly, because the water struggle to absorb into the center of the sphagnum mass, as well as struggle to dry out if it does get wet, leading to root death of either extreme (over/underwatering).
In recent years, coconut coir has been used, but not only is it poor with water retention (so should only be used in greenhouses), but many sources of coconut coir have come from trees that have been contaminated with ocean salt. Ocean salts are lethal to nearly all orchids, with a few exceptions from sea-level-growing orchids like Brassavola nodosa and related species.
Choosing the mount
- Driftwood – Use driftwood at your own risk. Often times, driftwood is sold as “washed” or freshwater, when in fact, it was harvested from either saltwater sources, or not washed thoroughly enough. This leads to death of the orchids by salt poisoning.
- Cork – Cork bark is the standard for orchid mounting, as it’s resistant to breaking down, pH-neutral, cheap, and available. The only downside to cork is that it does not allow airflow around the roots as they burrow into it, but that’s usually not a problem, so don’t worry about it.
- Tree fern bark – Truly the platinum level of orchid mounting. Expensive, but effective especially in humid terraria/terrariums and greenhouses for the healthiest roots, but not for every orchid type. Not recommended in drier environments, because it is porous and actively wicks water into the atmosphere.
- Terracotta – Similar porosity to tree fern bark, and recommended for humid environments like greenhouses and terraria/terrariums.
- Other – Plastic or inert materials are ok, but the materials mentioned above cultivate the necessary symbiotic bacteria and fungi that orchids need to thrive. If you live in a tropical environment, or if you have a tree in the greenhouse, and choose to plant on a tree, that is also acceptable. Just note that some orchid species are tree/mount specific. There aren’t incredibly many that are selective, but enough are to be worth mentioning.
