Oncidium and tolumnia question

[Roberta]

Culture for Oncidium vs. Tolumnia is quite different. Oncidiums want to stay damp, they should never dry out. So small bark is appropriate for them. Losing leaves on the oldest pseudobulbs (and seeing them shrivel) is normal - all the energy is going to the new growth. But they do need water.

Tolumnias, on the other hand, are dominant epiphytes. They need to dry out between waterings. They really do best mounted, or in baskets (with little media, needs to be very fast drying if you use it at all).