Need advice re-potting my 7ft cactus

[Cactastrophe!]

Hi everyone, my 2 metre cactus is in desperate need of re-potting. Its soil has not been changed in about 3 years and because it grew so tall, its not getting the south facing sun it deserves. I am transporting it to a new location with more sun and will change the soil at the same time. Please can you give me advice on re-potting it.

1. It is currently the 2nd month of Autumn (Fall) in the UK and I know its not the best time for re-potting but, as long as its not going to be
cactastrophic, Its the only time I will get for the next 6 months. Can I go ahead and do it?

2. I'm not sure whether to put it into a larger pot. The one its in at the moment is 25cm (10'') internal diameter and the next size up I have
is 33cm (13'') internal diameter.

3. They also only have one draining hole in the middle with a 2cm diameter, do you recommend drilling new holes? If so how many?

4. Should I try to shake off and get rid of all of the old soil before putting new cactus soil in or should I leave some of it?

5. Should I support it after re-potting it?

[DaveW]

Soil looks a bit rough, but evidently growing well in it. You can repot in winter provided you do it in dry soil and do not water until the plants start into growth in spring again.

With Cerei being gross feeders you can often overpot compared with globular cacti and a large heavy pot is often needed to prevent a tall plant falling over. Sometimes putting its pot into another larger pot and packing around it to give added weight and stability.

I would surround the plant with bubble wrap or something similar. Tie a wooden batten or stake the length of the plant to it to support the stem and stop it breaking then take the plant outside and carefully lay it down horizontally, again on bubble wrap or old carpet. You may need an assistant for this, and gradually work the old pot off and then fill the new pot up to the correct level to go underneath the roots and lift the plant up then and fill in around it with new potting soil. You may either have to hold it up yourself and get somebody to fill in the soil, or vice versa.

You will probably need to support it until the roots get hold tying it to one of the stakes you used to stop it breaking but of course after removing the bubble wrap. Another idea for supporting it in this video.

https://www.youtube.com/watch?v=xrg80CK3bPA

[Aiko]

1. I would wait. No rush.
2. Depends on how much roots the plant has. But my guess is that the current size is fine.
3. One is probably fine enouh. If it is easy to make more, just go ahead. The amount of holes is not important, but it is beneficial if the holes are evenly spread over de bottom.
4. Yes, it is prefered to remove all old soil and totally renew the soil when repotting. Try to take as much as you can from the roots. But depending on the current soil and amount of roots, that might be a tricky thing to do. You will undoubtly pull off some roots when repotting, I suspect. Not a big problem. But be as careful as you can.
5. That is a wise thing to do. But it depends on how firm it sits once it has been repotted.
6. Yes, you should indeed tidy up your room. It's a mess!

[Cactastrophe!]

Thank you both so much for your help. Thanks @DaveW for your tips on re-potting (I am still worried about this stage :/) and video you sent has a lot of good info. Thanks @Aiko for your advice aswell (also that is my sisters bedroom and I share your thoughts on it).

[greenknight]

If you're changing to a different potting mix it's important to remove as much of the old mix as possible - water may not move freely between the two mixes, it might drain past the old soil ball without wetting it. If you're re-potting it with the same mix as before, it's not going to create any problem if you leave some of the old soil.

[PseudolithosLover]

So beautiful! What species is it?

[Cactastrophe!]

Not sure. Its Genera is probably "Cerei" as mentioned above but which one I don't know. It is just like a hexagon with 6 corners. There are 10 spikes in each group of spikes and a little fluff as well. You can try find it from this list:

https://cactiguide.com/cactus/?genus=Cereus

[Cactastrophe!]

It is just like this : https://www.rarexoticseeds.com/fr/grain ... ladus.html