Hi... in all my reading on here, when in doubt about watering don't.... if you think it is to wet, what I would do is take it out of its pot and take off as much of the wet soil as I can and lay the cactus on news paper or paper towels to dry out the soil and then repot with new soil, don't water it and give it a chance to recuperate.... cactus can go a very long time without water.... I don't water my cactus all winter in fact I just watered mine 2 weeks ago for the first time since last fall when I moved them indoors for the winter....all are doing fine, but I guess I over watered my stapelia..it rotted and I tryed to save part of it but it rotted too.... well, just passing on what I have learned from the people on here I hope this helps and I am sure others will help too...good luck.....linda

If it isn't mushy I wouldn't worry about it by the looks of things the stalk is just starting to harden and turn woody.. same as a young tree would as it gets older. The top of the cactus is a compleatly different cactus to the base that it is on ... if you are worried about the life of the yellow part of the cactus remove it and graft it to a desert cactus instead. It will help it live longer and gives it much better living conditions. The green part of your cactus is a compleatly different cactus all together and is actually a tropical cactus with different watering needs. It's like attaching a cat to a dog and feeding it fish food... neither will survive long unless you seperate them and give them the individual care that they need. both parts look compleatly healthy so I wouldn't panic, the stem is just coming into adulthood :)

I posted in here a little while ago with my moon cactus top that i had placed in a pot of soil and it was growing roots. Only the darker purple will do this. As it has just been an experiment for me so far I simply chopped it off when the base of the cactus got rot and placed it on a pot of soil. (Yes I am aware its not the ideal soil for succulents its probably about time I changed it over) Its been sitting on that soil now for almost 6 months and has grown a healthy amount of roots. I gently disturbed him so you guys could get a look at the roots so you could see for yourself, didnt want to disturb too much though so hopefully you get the gist.

Depends on whether or not the plant is completely red or not. In this occasion, since you did not specify its exact color. a photo would be very helpful. If the plant lacks chlorophyll- the red, pink, orange and yellowish cultivars need to be grafted at all times - they cant live on their own. The purple ones can- albeit growth speed and durability may vary. You may place them in coarse soil and see what happens - there was a topic about degrafting.