Question
Hi Maureen,
Please help me,i have a light green prickly cactus,raised from a tiny finger to a massive foot long plant.I recently repotted it,and when i put it outdoors on my balcony something happened.Maybe it got hit by a cat.When i brought it back in because of an unexpected frost,it fell over.I straigtened it twice,and then buried it deeper in the pot.The next day,the 'head' of it just fell over,leaving the hollow main stem exposed.What should i do please?
Sabina

Answer
It sounds like the base actually developed dry rot somewhere along the way (it might even have been the frost), thus the hollow base.  If there is healthy tissue - white, green, juicy- above the part that fell off, I'd cut it there and reroot that part.  Then I'd throw out the base, soil and sterilize the pot.  Your plant devel0ped a fungus or bacterial infection and all that stuff is contaminated.  Don't compost it.

If you look through some of my other answers I've written a lot about rerooting a cactus.

if you need more help, let me know.

Maureen