Platycerium ridleyi is one of the most striking and beautiful platycerium. It is difficult to grow. This species grows very high in trees. I am told that where Platycerium ridleyi and Platycerium coronarium are found together, it is always above the coronarium.
Subject to rots and other diseases, and a favorite of many plant eating pests. One problem is that this is a solitary species. This means that, if an insect eats the bud, the plant will die.
I had been told that Platycerium ridleyi almost always grows facing upward. Richard Sonnen recently visited Sabah, and he reports: "Incidentally, saw hundreds of P ridleyi in Danum Valley in Sabah and not one was growing on its back. All were clasping the tree sideways like other stags. They were always the highest epiphyte in the tree... over 200' up. Hasn't rained in 3 weeks so they are tough. Some were easily 4' across. One gorgeous treeful had a dozen huge specimens."
The plant below is a form from Burma, which was introduced recently. It is in a 10" Orchidbasket™.
Although it is very difficult and expensive to obtain tubular cork, this is how I have grown some of my finest specimens. This is the one I call Reggie's Large Form. The Ophioglossum pendulum (broad form) was added intentionally.
The veins of Platycerium ridleyi are raised. This species is inhabited by ants in habitat, and this means it likes good fertility and the substrate should be somewhat acidic.
All of the great specimens of Platycerium ridleyi I have ever seen have been growing high in a greenhouse. Good light and air movement are essential. In nature, ants inhabit the spaces between the shields, so this species likes fertile, acid conditions. I have had my best success keeping these plants very wet. Some growers are reporting success allowing it to approach dryness before watering. Where high humidity can be provided, this seems a good approach.
Platycerium ridleyi and Platycerium coronarium make a single fertile lobe on each frond. They are the only platycerium species that do this.