Carnegiea gigantea repotting/spots

[linkan]

Hi everybody!

I just got my hands on this nice speciment of Carnegiea gigantea but ive got a couple of question about it.
its said to be around 30yo and 140cm. The previous owner told me it was placed in kinda bad light the last year or so hence the bad growth on top.
It was also previosly potted in a quite organic soil, My idea is to use perlite/sand/soil in equal doses would this be suitable?
How should i handle the small black spots? And how long i should wait before potting it up again?
And is it okay to bury lets say an extra 30cm of the stem to get some more support on its weight?
The middle section where it looks shriveled up isnt soft or anything.
Biggest question at all is this one doable or is it already gone ? hate to see it end that way!

[greenknight]

I think it will be ok.

Don't bury it deeper than it was before - it won't ever grow roots upward into that extra layer of soil, so it will stay wet and probably cause the stem to rot. Stake it or put rocks around it if it needs support.

The mix you propose would be alright if you use coarse sand. Fine sand like beach sand is not good.

If the black spots are not soft, and they don't spread, they shouldn't be a problem. There is a black dry rot which grows very slowly, it gets into weak growth such as this cactus was producing. Get the plant stronger with proper soil and light and it should be able to resist the infection and stop it from spreading. The only way to get rid of it would be to cut it off - fungicides won't help, they are just preventative, not a cure for established infection. So just keep watch on it for now, you might not need to do anything.

[linkan]

Thx for the quick reply!

The sand i planned on using is 1mm or 0.0393700787 inches would this work?

[greenknight]

Thx for the quick reply!

The sand i planned on using is 1mm or 0.0393700787 inches would this work?

Yes, that should be good.

[oldcat61]

Good luck - the poor thing looks even more abused than the five footer I "rescued" last August. How big around is he? Seems skinny. Looks like you did a good job loosening the roots & removing the old soil. The tap root seems all curled; hope it will be happier in a new bigger pot. Do you have a spot in the sun for him? BTW, the color on mine looks good & he's fairly plump but I can't tell if there is any new spine growth. He's in a 2ft raised bed so I need hubby to climb up a ladder & have a lookee. Not sure he'll know what to check for. Good luck with yours - there's not much info on pot culture compared to those that are in the ground. Sue

[linkan]

Okay its potted up and im keeping my fingers crossed it will survive.
Its around 55cm at the widest point and a whooole lot thinner at the bottom, Hard telling from the previous pictures.
About the spot in the sun we will have to see about that, Ive got another much smaller saguro placed in an east window wich is doing great.
will probaly try it with this one to. And if its already dead or dying will it just fall over when it dies enough? Cause i dont want this boy falling on something or someone.

[CactusFanDan]

That's a Pachycereus, not a Carnegiea. They're often confused.

[oldcat61]

I wasn't sure from the photo & didn't want to be a killjoy. It doesn't have the big downward central spine of a Saguaro but thought that might be the poor growing conditions. If it is indeed a pringlei, that would explain why I thought it was skinny. Good luck & enjoy whatever it is. Sue

[greenknight]

That's a Pachycereus, not a Carnegiea. They're often confused.

I wondered about that, but it's in such a sorry state that I wasn't sure.

The circling taproot oldcat61 noted is not a good thing, but it doesn't look like it's going to strangle itself. Sometimes when a plant has been grown too pot-bound, girdling roots have to be pruned off to keep the plant from dying, but this doesn't look that bad - which is good, it would be awfully drastic to cut that big old taproot.

[linkan]

Sure looks like its a Pachycereus my mistake thanks for pointing me right. Might have mistaken on the other one aswell adding a photo of it.
About the taproot it was twisted like a spring about 3 times, but not strangling itself from what i could tell.
Might it be easier to cut the Pachycereus down and get rid of that really weak point at the bottom of it? How easily do they reroot?
Obviously in a year or so when its gotten better.
And i must say i really appreciate the help im getting from all of you!