| The only time to repot is when the newest growth is starting a flush of new roots, not after blooming or in the spring as some will yell you. Many plants grow their new growth at times other than spring, and a few will complete their new growth, stop for a rest (no growth going on), then throw out the flush of new roots on the completed growth just before they start the next growth. Cattleya amethystoglossa is like that, and it has a reputation for being hard to grow, mainly, I believe, because it is very sensitive to root disturbance, and if you repot based on the incorrect criteria, you will just about kill the plant. If the bark is breaking down, just watch your watering. Bad mix can be worked with to extend its use if you let it dry out completely between waterings, however long this takes. If it takes more than a couple of weeks, try watering with a reduced amount of water, and since you will not be flushing in that circumstance, use purified/RO/rain/distilled water and don't fertilize.
One caveat to the above is that if you pull the root ball from the pot to inspect the roots and the mix just falls away without harming any of the roots, you can go ahead and repot. BUT, you must be very careful of the roots when you put the new mix in so that you don't break any. The difficult part is that you want to press the mix into the pot well enough that the plant does not wooble, and here you have to walk a tightrope to press it in and not break roots.
Never divide a Cattleya to less than three mature psuedobulbs in a row (not counting back bulbs, which can be tossed if they don't look viable). Anything less than this will not bloom on the next growth. If you need to contain roots over the side of the pot, place a second pot adjacent, for the outside roots to go into. Mix or mixless is OK, just so long as the roots don't go below the depth of the older pot. Cynthia  |