I think no worries about the back spot. It may have received sunburn (the lighter area above it has that look), mechanical damage, or possibly a fungal infection that healed. The spot looks dry, so not spreading. Whatever caused the problem, the plant has isolated the damage.
As for a larger pot, it does look like it is ready. However, you need to wait until you see new little roots just start to emerge. It does look like there may be a new growth in progress to the right of the picture, but I can't see it clearly. That is where you would see roots. When you see them, you can go up to the next size of pot - not more than an inch or inch and a half (3-4 cm) more, enough to hold a couple of years' new growth, in medium bark. Catts need to be extremely well drained - the bark should let water flow through easily. They need to dry out before the next watering. Don't over-pot... these can be quite happy growing over the edge of the pot (they really don't like pots very much) In fact, if you have some humidity and/or like to water frequently (every couple of days in summer, perhaps twice a week in winter) you can avoid repotting altogether - just drop it, pot and all, into that larger pot, with no additional media at all. The air space between the pots is a bit more humid than ambient air, and roots grow into it readily. (This technique is used very successfully by Santa Barbara Orchid Estate in California. They are coastal, so humidity is good. If it fits your conditions, worth a try)
|