Improve Your Garden Soil
Discusses the basics of the Gardener's Loam - a man-made soil ideal for plant cultivation. With information on soil acidity, testing, composting, and fertilizing.
Includes basic considerations, water drainage, and moisture conditions at time of working, erosion, texture and structure, soil and other related facts.
The Schundler Company
Discusses about horticultural uses of perlite and vermiculite, with horticultural plant guides and photos.
Lays out a set of guidelines and suggestions on how and where to get vermiculite.