Here's the roof garden about 1/2 done--in place after the rains.
The kalanchoes, both lavender and and red, have almost doubled in size. Winter is the growing time for many of the succulents, but remember --- some rest in the winter, and need summer water, and a dry winter (you've already heard the sad story about the mammallaria who got watered at the wrong time.)
There are no sempervivums in this particular roof garden, as it's too hot a spot for them. The west sun beats on the plants from noon until sundown.
However, it's "growing from seed" time for sempervivums . The plan is to have another roof garden facing east which gets little or no direct sun, but lots of light. The semps should be happy there. The seed is here , and has been planted. It's an experiment. Otherwise the plants will be ordered in sufficient quantity for the east facing roof garden as suggested by Gwen Kelaidis.in her book. The ones in the picture came from Squaw Mountain and are growing in a pot until the East Roof Garden (move over Michelle) is ready for them.
The "chicks" root right away if planted elsewhere. Some are growing on the planting mix of a stag horn fern. The semps never missed a beat- started growing right away.