You should repot an orchid when its white roots begin poking out of its pot, as this indicates that the plant has outgrown its current pot and needs more space.
Purchase a pot at least 1 to 2 inches larger than the current one. Put your potting mix in a large container and pour boiling water — almost double the amount of the mix — on it.
Let the mix cool down to room temperature before draining it, and combine ½ cup household bleach with 1 gallon of water to make a DIY antibacterial solution.
Soak gardening tools and the new pot in the solution to protect the plant from bacteria and other germs. Pull out the plant from the old pot and clean excess dirt off the roots.
Use sterilized scissors to cut brown, rotting roots. Add the pre-soaked potting mix to the new pot and place the orchid before using chopsticks to add some
Finally, add some fertilizer to the mix and pour water until the pot is soaked so the plant thrives in its new home. Do this once a week to encourage the growth of new roots.