Repot orchids by removing them from their old containers, trimming damaged and diseased roots, and planting them in fresh orchid potting medium. Repot orchids when they are growing out of their containers, there are too many roots, and the pot drains poorly. The best time to repot is when they just finished flowering. Repotting helps orchids thrive and flower.
Gather materials, such as a knife, scissors, new orchid pots and potting medium. As orchids are sensitive to bacteria and germs, disinfect materials by dipping in a solution of half cup household bleach mixed with a gallon of water. Disinfect the new potting medium by covering it with boiling water and letting it cool before use. Wash your hands before proceeding.
With a knife, loosen the roots by circling the inside of the pot, and remove the orchid from the pot. Loosen the old, rotted potting medium, and cut off any dead, damaged or soft roots. If all the roots are healthy, pot the orchid in a container one size larger. Choose containers that have drainage, and avoid containers that are too large to prevent dead spots from developing that contribute to root rot. Overly large containers also discourage flowering and encourage root growth instead.
Place the new orchid medium in the pot, adding coarse material, such as foam and broken clay pots, at the bottom to improve drainage and the rest of the potting medium on top. Position the plant in the center at the same depth it was before, and add fresh medium around it or tie it to a wooden stake with soft twist ties so that the plant does not wiggle. Orchid medium typically consists of fir bark, sphagnum moss, fern fibers, coconut husk and perlite.