When repotting orchids, it is important to use an orchid-specific potting mix that is porous and provides good drainage. Orchid potting mixes can include materials such as sphagnum moss, fir bark, coconut husk, tree fern fibers, perlite, and horticulture charcoal. It is generally recommended to repot orchids every one to two years, or when the potting mix begins to decay or the roots become tightly tangled. When repotting, it is important to remove any dead roots, gently loosen the roots, and place the orchid in a pot that is 1-2 inches larger in diameter than its original pot.