I have several astrophytum growing out in the full sun of my backyard, and while some are a tad yellowish from the immense sun, all are doing great. I water them about once or maybe twice a month, but one always seems to get to excited about the water, and he sucks up too much , and his poor skin splits. Nearly every time he gets watered, a new spilt appears somewhere on the skin, with the latest one being somewhat deep. So what could be causing the splitting? He's an A. myriostigma 'Quad' , and it's definitely not poor soil, as it had some of the best gritty, pumice-y soil a cactus could have, and he is the only one splitting.
I can post a pic tomorrow if needed.
Thanks in advance!
-zeck