I bought my cactus about 15 years ago and I have to admit I knew nothing about them other than they didn't like watering very often. So he was watered infrequently. I was very naive. He would occasionally flower, and currently has quite a few buds appearing. Just recently I started looking into cacti more and feel really bad that I unwittingly neglected my little guy over the years. He's now getting much better care, has been repotted in special soil, and is watered more frequently in growing months and less in Winter. He appears healthy except for the fact that his spines from the bottom have all gone brown and brittle. This worries me quite a bit. He has always sat in my south facing bedroom window, which does have a radiator next to it. Could he be drying out? Is the heat causing this? We have an outdoor room that is much cooler, close to freezing in Winter, would this be better for him? Any help would be gratefully appreciated.