Orchid plants must be re-potted when they outgrow their containers. When the growing medium in which they are planted is degraded to the point that it has a spongy consistency and remains saturated instead of draining freely, the orchid must be re-potted with fresh medium. Do not re-pot your orchid while it is blooming.
Put a few layers of newspaper down on a table or bench. Place your hand over the top of the pot with the orchid between your fingers. Turn the pot upside down. Hold the plant up high enough that it does not hit the work surface. Thump the bottom and sides of the pot with your other hand to dislodge the potting medium and roots. Set the pot right side up on the table or bench and slide a butter knife around the inside of the pot to loosen the medium and roots if it does not break free easily. A few roots may be slightly damaged but that will not harm the orchid. Turn it upside down and thump it again. It should slide out.
Work the roots apart with your fingers and remove as much of the old potting medium as you can. The roots do not need to be bare. A little of the old medium left on the roots is OK.
Remove damaged or dead roots that are light brown and spongy with a heavy sharp pair of scissors. Wipe the scissors with rubbing alcohol and a cloth before and after use to control the spread of viral disease.
Divide the orchid by cutting through the rhizome with a sharp knife if there are at least two new leads or growths. Be sure to sterilize the knife with rubbing alcohol on a cloth before and after use.
Determine the size of the new pot based on the orchid’s rate of growth. Use a pot that will allow for two years of growth. Wash old pots with dish detergent, rinse well, then soak them in 10 percent chlorine bleach solution for 30 minutes. Rinse the pot thoroughly. Allow reused clay pots to dry for a few days after washing and sterilizing. Soak new clay pots in water for five minutes before re-potting the plant.
Wet the potting medium with boiling water. Let it cool, then drain the water. Put a layer of broken clay pots or foam peanuts in the bottom of the pot. Place a layer of rinsed potting medium on top of the bits of clay pot or peanuts. Set the orchid in the pot. Add the potting medium a little at a time and tamp it down firmly around the roots with your hands as you pour it in. Fill the pot with potting medium until it is level with the top of the rhizome.
Stake the orchid securely for a few weeks until is has enough new root growth to support itself. Place the orchid in a shady location and mist the plant and medium twice each day. Move the orchid back to its original place and resume normal watering and fertilizing after new root growth has been established.