Hi Barb,

If you do a search here for Semps you will be presented with all kinds of information on container types and soil mixes, etc.

The Cacti & Succulents forum has bunches of info as well.

I have semps growing in regular garden soil wedged between rocks (in my open garden) and well drained soil containing very little organic matter in my alpine troughs.
Consider where they grow in the wild, it's pretty tough out there!
Lean and mean seems to be the way to go, and good drainage is really important, so make sure you have drainage holes in your containers. Semps don't like wet feet.

I am by far no expert but that's what works for me.

Hope this helps.
-GardenChicken

Here is a link that might be useful: check here for some soil info

In my zone semps easily rot in containers in midsummer. The heat and moisture are the culprits. They appear to go dormant in mid-summer so I water very sparingly at that time but still lose a few every year. Here they do better in the ground, even with the very dry, hot summers and very wet, mild winters. Make sure they have some protection from the heat and excellent drainage.