Terrarium substrate non-perlite
Jane McGary (Wed, 30 Dec 2009 10:49:21 PST)

A fast-draining mineral alternative to Perlite is horticultural
pumice, which can now be purchased in small quantities in many garden
centers in areas where this rock is not "native." Also, I think an
attractive way of growing some of the more epiphytic plants in a
terrarium would be to plant them in thick moss growing on a rock, if
you happen to live where such mossy rocks can be obtained (I know,
probably not in Arizona). My woods have big piles of rocks dumped
there many decades ago by farmers, and because these rocks have a
porous surface layer, they host lovely mats of moss, in which I've
planted such things as certain types of Saxifraga, small Heuchera,
and ferns. I'll bet some of the small species of Asiatic Primula
would do well, and also some of the gesneriads. Keeping the moss
planting in a closed environment would provide enough humidity to
prevent the moss going dormant in summer.

This is getting pretty far from bulbs, I admit!

Jane McGary