I have this cactus for for around 8-10 years and bought from IKEA. It grew fast at the start on my sunny windowsill (normal indoor plant soil) for a few years and I had to repot 2-3 times. I am watering this cactus like 1 time a week and never changed that and it always was in sunny bright light locations . Within the past 4 years it got some sunburn during a very hot summer and I put it in a bit more shade but still bright location and it was fine there aswell. I then repotted it and put it in cactus soil and from then it started to decrease in health . So I put it back into normal soil again and it was stable there. Now it started to develop a dark green ring on the upper part which soon dried out and now is dead . I don’t know a lot about cacti 🌵😭 I mostly own other plants which are in good health overall. Is it over ?
by hokeypokeydemon