Bev that's a good idea! Pat if you know how large each individual semp gets that will give you an idea of how much space they need. They're very easy plants in this way. If you didn't give them enough room, they just cluster up!!
Enjoy the project, it sounds fun! Remember that even though these are succulents, in the hot summer they do like some water, they have short roots typically so they don't need "deep heavy waterings"
Cheers
