I saw your tags on that dehydrated cactus post and was wondering if there’s a good method for getting rid of really compacted soil to change it? I have a massive cactus that was like that when I bought it, and although I’ve been watering it weekly through the summer, the soil is still really hard, and I worry about damaging the roots.
So for cactus and succulents do not worry about damaging roots. You can chop off all the roots and they will just grow new ones in time. So really you can't damage the roots enough to kill them, I promice*.
So for my succulents when I get them and their soil is super compacted I actually stick their roots into a bucket of water. Let it soak for a bit. Then I stick my hands in there and help massage it off. This can sometimes take awhile. Standing/sitting there for 10 minutes massaging soil can feel like a lifetime, but it will eventually come off. If you rip some roots off, oh well, the plant will be better off in the long run in better soil so the damage is negligable. I'll change the water depending maybe once just so I'm not working in mud, and will do a final rinse so I can check how the roots are. Then I just leave it out bare root to dry with a fan on the roots for a few hours. After that I'll repot into half/half soil/perlite (cactus could even do more perlite/grit if you want) and leave it dry for a week at least. Cacti I can leave for like 3 weeks. Then they'll get their first water after being repotted. Make it a soak.
How you do all this with a spikey cactus I have no clue. Wrap it in blankets/towels and be prepared for you never being able to get the spins out of those blankies or towels ever again? Newspaper and styrofoam? It's really up to you have you handle the spikes. Good luck! Worse comes to worse you just chop off the roots and reroot it directly into better soil.
*This is not true for some mesembs, like Lithops and Split Rocks, they have a main taproot and will die if that is removed. They do not regrow their taproot.








