Cymbidium orchids are a species of epiphytic orchid that are large plants in comparison to most orchid species. They are grown as both indoor and outdoor plants and produce tall spikes of large wax like flowers in pastel hues over thin strappy foliage. As epiphytic orchids, cymbidiums have a surfboard shaped green pseudobulb at the crown of the plant that stores water and nutrients collected by the roots. Cymbidiums are not planted in typical garden soil and must instead be planted in a coarse and easy draining material to prevent root suffocation and rot. Preference for one medium over another varies by grower but easy drainage is the key factor.
Commercial Bagged Orchid MIx
Purchase a premixed coarse orchid planting medium designated on the package for epiphytic orchids. Chinks of redwood bark, osmanthus, horticultural charcoal and perlite will be identifiable through the bag.
Mix Your Own Bark Growing Medium
Blend your own house special orchid medium to save on cost and trips to the nursery. Mix 2/3 fine fir bark with 1/3 fine redwood compost that resembles a combination of small chinks and fine splinters. This will provide good easy flowing drainage but will also hold some moisture in the medium long enough for the roots to absorb it.
Mix Your Own Charcoal, Vermiculite & Moss Medium
As an alternative to planting your cymbidiums with a bark medium create a bark free blend. Mix 1/3 horticultural charcoal chunks with 1/3 vermiculite grains to lighten the mix and add a final 1/3 of milled sphagnum peat moss to hold moisture. You can grind up chunks of peat moss in a utility blender if you cannot find it available finely milled.