Baja_Costero said:Put it in front of a window where the sun hits the plant for hours a day and it may recover. I'm not quite sure what went wrong but strong light should help. That north facing window will not provide enough light during the darker half of the year, and it may not even provide enough light now. Ideally the plant should "see" the sun. That will also aid with watering.
WillC said:Your plant has a very small, fine root system that can tolerate drought but not constantly damp soil. The pot is too big and the potting mix lacks porous material such as perlite mixed throughout. That means the soil lacks porosity, stays wet for too long and the roots are suffocating. Heat and light are not problems.
You might consider carefully unpotting the plant and gently removing most of the soil and any dead roots. If there are still some live roots remaining, repot it into a very small pot with a potting mix of 3 parts peat moss and one part perlite. Keep that mix barely damp while roots are forming. Warm temps and lots of indoor sun will help.
Baja_Costero said:It really sounds like you are watering exactly as you should. Here are the boundaries to stay within. There is no benefit to allowing the soil to stay bone dry for any extended period of time. (Underwatering.) There is however a risk of rot if you water before the soil has had a chance to go dry or near dry at depth. (Overwatering.) Imagine a cycle of properly (dripping) wet and properly dry (at finger depth) and that's where your plant will be happiest. Be aware that in the darker and colder days of late fall and early winter, you probably will have to cut back on how often you water.
There are as many cactus mixes as you can imagine, but as a general rule they should drain fast (not hold onto a lot of water) and have gritty components, not fine ones. I have used a variety of dedicated cactus mixes but at this point I use regular potting soil, mixed with pumice. I have some plants doing fine in an all-organic mix from the days back when I didn't cut the soil with extra rock. Some Echeverias aren't real particular about drainage. But as a general rule they like about 50% rock. That simplifies the watering too, as the soil dries out faster and more predictably.
Baja_Costero said:Lay them on top of the soil, not buried in it, and there is a chance they will sprout new rosettes.