How to repot this bruiser of a cactus so it doesn't lean

[Aridane]

I have posted before about this bruiser of a cactus which Nanthewiser identified as a (very etiolated) Ferocactus, and possibly F. hamatacanthus,

And here is the absence of root, just a few desiccated strands showing... . .

(and here it was in February this year, after its January watering - etiolated but green and thriving)

Well, tbh it doesn't look too good, I'm afraid. If you are going to cut it, I would probably cut about half way up (or down) in the hope that you will see healthy green tissue. Use a very sharp knife, and if it isn't healthy make another cut further up (you're supposed to sterilise the knife between cuts to avoid contaminating healthy tissue, with something like surgical spirit or a flame). You'll then have to allow the cut to callus - dry up - which will probably take several weeks at this time of year, before placing it very gritty compost (as mentioned above). Don't water it! It might start to send out roots after several months, but this time of year it could be longer, so maybe not until spring. These will appear as small, pale nubs around the base of the cutting, and when (if) you see those, you can gradually start to water it.
If I'm really honest, I don't think it will be successful I'm afraid, but if you don't try, you won't know, so I wish you luck and hope I'm wrong!

Thank you for your honesty and advice, Nan . I will give it a go, with low expectations. Though who knows, I might be posting next summer with a nice update. And, if not, well, I have enjoyed this cactus for 40 years,.

And I have learnt a lot from this thread!

Once you've cut as Nan describes, do a post-mortem on the base. Is it soggy inside? - this would suggest that at some stage it has been too wet and too cold (wet in hot weather is OK but not ideal, provided it dries out between waterings, cold (but above about 5deg) and bone dry is also OK). Fluffy white stuff in the soil around the dead roots would indicate root mealy bug - but I think you would have mentioned that!

Fascinating advice and pictures. Good luck OP I hope to see something exciting happen in a few months.

NanTheWiser does this mean its possible to propagate with a wedge or section?

@Neome, only in certain cases. Some cacti can be propagated from a section of stem, but a wedge wouldn't work (except for grafting, which is a skilled operation).

So I cut the cactus half way up - this is what it looked like.

Top half now resting on a plate in the spare room to callous over

And here is a close up of the severed cactus.

The top bit is the bit on the right hand side.

The indentations on the bottom bit - left hand side - are where I poked the cactus to see if there was 'give' or whether it was rock hard. It was springy

I had a go at a full autopsy with the bottom half. I used an electric saw to cut the very bottom bit off (feel very CSI) and the 'flesh' was hard and woody like the core of a pineapple

I had your cactus's twin OP, bought as a present for my parents when I went to Tenerife 16 years ago.
Mum got fed up with it stabbing her so gave it back to me about 5 years ago - and it appeared happy leaning up against the wall on the window sill....until it rotted off, just like yours.
I binned it, being totally unaware that I could have tried what you're doing.
I too have killed an aspidistra and had a good go at a sanseveria too 🙄😄

Missing the point of the thread, but I had that exact knotted penguin as a child! I called him.... Pengy!

This is fascinating! I've never had such a result with cacti. Is your plant getting sunlight or is in the passage way?

@Strawberrycreamsundae - the surgery probably won't save it but it's worth a go. I was quite shocked when NanTheWiser suggested it - because it feels so counter intuitive cutting a cactus in half (!) - but after a week I realised there wasn't any real downside.

I too nearly killed an aspidistra - that's a separate thread where other posters, including NanTheWiser Were helpful again. Turns out, ahem, Imjust hadn't watered it and it was sitting in dust

How did you kill your sansevieria and aspidistra - overwatering?

@Cat0115 - NO!!!

Can I ask how old you are (decade will do)

@TeaAddict235 - it was getting sunlight in the afternoon (on a side table in the living room) but was too big for a window sill.

A few years ago I left it outside for the frost free period of the year in a very large terracotta pot and it went a bit exuberant in its growth

That looks nice and clean, Aridane, no rot as far as I can see. Now just leave it alone for a few weeks until the cut surface calluses, which will look like a whitish skin. Then follow my previous instructions, cross your fingers and hope for the best!

Will do, Nan - and I'll post again next spring! To confirm death or slow resurrection of cactus.

In the meantime I have been telling my neighbour about the cactus that grows in the Atacama desert and doesn't get any rain but 'drinks' fog - see what you've done, Nan . (In my defence, neighbour was a bit baffled by me wielding an electric saw and doing a cactus autopsy)

Well we're often considered a load of nutters, so welcome to the club!

In the meantime I have been telling my neighbour about the cactus that grows in the Atacama desert and doesn't get any rain but 'drinks' fog That's what "air plants" do too. Moist air also cuts down evaporation from the leaf surface and therefore cuts down the passage of water through the plant meaning it doesn't need so much water at the roots - hence things like epiphytic orchids which don't like sitting in wet soil. Cacti cut down evaporation by not having leaves (reducing surface area), by covering themselves in white hairs, and by having a different metabolism so they can close their pores during the heat of the day.

Look how other worldly this picture of the Atacama desert and the cactuses that receive no rain but drink fog!

I nearly posted that pic yesterday. These cacti grow right on the coast line where they take advantage of the sea fogs that roll in.
Here's a pic showing a huge clump in the fog. That clump must be hundreds of years old, but they are at the mercy of changes in weather patterns, and some colonies have been completely wiped out in recent years.

awesome cactuses :)

Sad update:

@NanTheWiser and @RolytheRhino’s fears On cactus survival have been well founded.

Sliced cactus grew pinprick black mould spots which rapidly took over (non callousing) cut

And the brownish exterior of cactus evident on part of the bottom half rapidly spread up the cut top half, and the cut but started to recede into itself