I have 2 Crassula ovata (regular leave type) where the underside of new leaves is red. The one that first demonstrated this was a cutting and I thought that maybe it was because it was sitting on a windowsill right next to the radiator. Last week I noticed that this is now happening to the new growth on the mother plant as well and that one is kept in another room on a window table with the closet radiator across the room. The redness is only on the underside too, not on the edges of the leaves like is typical on jades. What are they trying to tell me?

I know I saw this question in the middle of a longer thread a month or so ago but I didn't end up reading any replies before I forgot what thread it was (and the search function brought up all sorts of not what I was looking for). So, thanks for reitterating yourselves!