I have been growing hens and chicks for the past couple of years. I don't know which ones I have but I think they're great. I have noticed that on some of the plants the leaves on the outside will at times turn yellow, become almost kind of spongy in appearance and die. Is this too much water? Too much exposure? Bad soil? I want them to be green and healthy and those odd looking leaves are most vexing.

Thank you.

Kate