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Do I have to use cactus soil if I want to make a rock garden?

I want to make a small rock garden with these plants: Anemone Pulsatilla Draba Rigida Campanula Rotundifolia Should I use cactus potting soil? Or should I make layers or different soil? I read somewhere I should put sand on top and regular potting mix in the bottom, with gravel on the very bottom to further improve drainage. But what do they mean with "sand"? Do they just mean cactus potting soil? If it's real sand, can you tell me where I can buy it, because I am sure it must be some kind of fertilized sand. Do they sell it at the Home Depot or Lowes? Most importantly, my zone is Z8a, in the Dallas area. Thanks!

Public Comments

1. You need to create a free draining compost for them to grow well in. A mixture of ordinary garden soil (preferably not clay) grit, gravel and sand mixed together is fine. None of these plants are particularly deep rooted so as long as the soil they are in drains well and you top with grit or gravel so water does not sit around the neck of the plant they will grow fine. In UK we have a bagged compost called John Innes and this is a soil and sand based compost with no peat. Peat is about the worst thing for these plants as it holds too much water and they will rot. Your zone is fine for them too.
2. These plants all require well drained soil. You want the consistency of cactus soil, but there is no need to go out and buy it when you can make your own. You want to use a peat free soil, some perlite and clean play sand. Mix 20% sand, 20% perlite (moisten before you use to keep down dust) and 60% soil. Toss and there you go, cactus soil! To test, moisten a handful and try to form a ball by squeezing in your hand. It should not clump. If it does, add a bit more perlite and sand. Make certain you have a drain hole in the container, and I would not bother using gravel, it may just plug up the hole. Be certain to water well then allow to dry out slightly. Keeping the roots moist will kill the plant! No saucer under the container please!!! :) An all natural liquid fertilzer like fish emulsion or compost tea will be good for these plants. Hope this helped! Happy Gardening!