Soil, known as dirt outside the garden, is the most essential component of a successful garden. Many gardeners must improve their soil to get the consistency and fertility needed to grow flowers and vegetables. It takes time and amendments to improve bad soil to correct pH, make nutrients available and allow drainage. The ideal garden soil is called loam. Loam is a combination of large particles that provide drainage and room for roots to grow and small particles that are nutrient-rich. Good soil contains microorganisms and earthworms that aid in decomposing organic matter.
Test your soil. Take soil samples from multiple areas of the garden and three different depths. Be sure soil is free of plant materials. Send bagged soil to a professional lab, usually associated with your state's agricultural college or extension office, for analysis.
Review your soil test report, paying particular attention to soil pH, particle-size distribution and cation exchange capacity--the degree to which soil can absorb calcium, magnesium, potassium and sodium.
Correct soil pH to neutral or slightly acidic---between 6.5 and 7.0. Raise the pH in soil by adding hydrated lime, and lower it by adding elemental sulfur or aluminum sulfate.
Improve soil consistency to get better soil and particle size distribution---10 to 30 percent clay, 40 to 60 percent sand and the remainder silt. Silt particle sizes are in between clay and sand at .002 millimeters to .05 millimeters. Adding organic matter and humus (decomposed organic matter) improves the consistency and cation of both clay and sandy soils.
Grow cover crops or green manure such as alfalfa, legumes, rye grass or buckwheat. Turn the green mature crop into the soil to decompose and add nutrients that improve the soil.
Add animal manure to improve the soil's trace nutrients and nitrogen. Dried or seasoned manure is best because the weed seeds have been killed by heat. If using very high nitrogen animal manure like bat guano, distribute it lightly in areas where plants are growing to avoid nitrogen burn.