Parodia erubescens (I think) repotting help

[CactusRoommate]

Hello!
So I bought this guy about 3 months ago, and the identification thread basically agreed it was Parodia erubescens (Notocactus). I would like to repot him, since all the threads here are telling me that stores often sell them in the wrong type of soil, but I have no idea where to start or how to do it correctly.
Could someone please suggest a soil mix that would suit him? I live in Montreal (Canada), so we have long cold winters and short hot summers. I'm not sure if that affects anything, but just some background information
Also, I'm not sure how big the pot would have to be! I have a cute terra cotta pot that I found in my garage, but it's about the same diameter as the cactus. I'm not sure if they need more space around the sides or not.
Finally, could someone please give me some basics on the repotting procedure? He's my first cactus and I really don't want to hurt him...
Thank you very much for your help!!

[iann]

That pot is a suitable size and normally you wouldn't pot on to anything bigger, but it is a good idea to replace the soil. A similar size pot is probably the right size.

Search this forum for soil recipes. The basic idea is simple enough, but finding suitable ingredients can be difficult. Paradoxically, any product with the words "cactus soil" written on them are almost certainly unsuitable.

When you get the plant out you mat find that it is in a very hard lump of peat, but it is best to remove this even if you have to lose a lot of roots. This is the time to see what roots you have and decide what size pot is going to fit. You don't want to pot on much beyond the size of the roots, and only really need to go bigger when the roots become really constricted.

After repotting, don't be in a hurry to water. Especially if you damaged the roots removing the old soil, you have to let the plant heal itself before getting it wet. You could even get it out now and leave it without soil while you for hunting for pots or soil. It won't be harmed by a few days, or even weeks, sitting around naked.

[CactusRoommate]

Thank you!
The pot I had in mind is a very similar diameter, with one decent-sized hole in the bottom. It's made of terra cotta though, and I saw a couple of threads saying this was not a suitable material for a pot?
Is there a material you would recommend?

[iann]

You can use porous terracotta although I don't think it is ideal. It causes very rapid drying of the soil by evaporation which can lead to a number of problems. Nothing immediately fatal but over time things will be less than ideal. Especially when used as a "solution" to the problem of soil that holds too much water (or a heavy hand on the watering can), it just compounds the problem.

Plus those large holes are a pain. You can sometimes get away with it using a very fibrous peaty soil, but with anything suitable as a cactus soil, it will just fall through the hole. Some form of porous covering, such as window screen, over the hole can keep the soil in and still let the water through. Very small porous pots dry out so fast you could even get away without a hole in the bottom, but you didn't hear that from me

[CactusRoommate]

Haha, thanks a lot! I'll keep all that in mind when I go pot shopping