» Improve Your Garden Soil
   Covers a wide range of garden soil topics, including soil types, pH, nutrients, testing, composting and fertilizers.
   http://www.improve-your-garden-soil.com/

» 6 Functional Group Guide for Soil
   Microbiological components of a soil bioassay.
   http://www.bbclabs.com/six_soil.html

» Better Homes and Gardens: Soil, Water & Fertilizers
   Includes articles on making potting mixes, proper watering techniques, nutrient needs, and mulching.
   http://www.bhg.com/bhg/category.jsp?catref=C401

» Do It Yourself.com: Fertilizer, Compost, and Soil
   Series of projects, articles, and tips on fertilizing, composting, and nutrient management.
   http://www.doityourself.com/scat/fertilizercompostsoi

» Gardening Information: Soil
   Collection of articles from Oregon State University on various aspects of soil: use of amendments and cover crops, temperature, acidity, moisture, and testing.
   http://extension.oregonstate.edu/news/category_search.php?searchCat=soil

» Improving Soil
   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.
   http://www.rodsgarden.50megs.com/improvingsoil.htm

» Improving Soils For Vegetable Gardening
   Ohio State University fact sheet covers soil basics: types, texture and structure, drainage and moisture, nutrients, pH, and cover crops.
   http://ohioline.osu.edu/hyg-fact/1000/1602.html

» Iron Chlorosis
   Explains how iron deficiency affects trees and plants, and how to correct it. Ohio State University fact sheet.
   http://ohioline.osu.edu/hyg-fact/1000/1009.html

» Lead Contamination In The Garden
   Covers causes and effects of elevated lead levels, recommends both health and soil screening procedures, and provides guidelines for gardening in areas with lead contamination.
   http://ohioline.osu.edu/hyg-fact/1000/1149.html

» Soil Testing is an Excellent Investment for Garden Plants and Commercial Crops, HYG-1132-99
   Ohio State University fact sheet covers the benefits of testing garden soil and provides recommendations for testing frequency, collecting a sample, and submitting to a testing lab.
   http://ohioline.osu.edu/hyg-fact/1000/1132.html

» The Schundler Company
   Collection of articles and resources about the horticultural uses of perlite and vermiculite.
   http://www.schundler.com/hort.htm

» The World of Soil
   An introduction to soil components, acidity, fertility, and care, as well as an extensive collection of links to other soil resources.
   http://web.ukonline.co.uk/fred.moor/soil/

» Vermiculite.com
   One-page site giving suggestions on where to purchase vermiculite in the United States, along with some uses and properties of vermiculite.
   http://www.vermiculite.com