| Vermiculite.com http://www.vermiculite.com/ One-page site giving suggestions on where to purchase vermiculite in the United States, along with some uses and properties of vermiculite. | |
| The World of Soil http://soil.hostweb.org.uk/ An introduction to soil components, acidity, fertility, and care, as well as a collection of links to other soil resources. | |
| The Schundler Company http://www.schundler.com/hort.htm Collection of articles and resources about the horticultural uses of perlite and vermiculite. | |
| Improving Soil http://www.rodsgarden.50megs.com/improvingsoil.htm Oregon horticulturalist offers information on soil components, pH, testing methods, and nutrients, and means of improving it by using amendments and improving drainage and aeration. | |
| Do It Yourself.com: Fertilizer, Compost, and Soil http://www.doityourself.com/scat/fertilizercompostsoi Series of projects, articles, and tips on fertilizing, composting, and nutrient management. | |
| Colorado PlanTalk: Iron Chlorosis http://www.ext.colostate.edu/ptlk/2115.html Explains how iron deficiency affects trees and plants, with links to more detailed information. | |
