Rodale's Ultimate Encyclopedia of Organic Gardening has some very wise and concise words to say about soil: "Healthy soil is the key to successful organic gardening. The basic principle that organic gardeners live by is to feed the soil, and let the soil feed the plants. The challenge for organic gardeners is to balance the soil so that it provides all the conditions plants need to thrive". (p. 541)
The biggest investment that you can make in your garden is improving the soil. Even if you imported completely new topsoil, you will likely want to adjust the pH and add amendments to change the nutrient profile so that the vegetables and flowers you cultivate will thrive in optimum conditions. The following products can help you nurture the most valuable component of your garden.