Soils are classified by the size of the most prevalent mineral component, and are generally described as sandy, clay or loam. Sand particles are relatively large and round, and fit together loosely; think of a bucket full of tennis balls. Clay particles are small and flat and pack tightly together; think of stacks of pancakes. Loam is comprised of a good balance of sand, clay and silt (silt is defined as particles of the earth that are somewhere in between sand and clay in size).
Sandy soil warms quickly in the spring, is light and easy to dig, drains quickly and contains a lot of oxygen. It doesn't retain water or nutrients so it dries out quickly and doesn't offer much in the way of plant nutrition. Unless you are growing plants that are adapted to sandy soil, plants grown in this kind of soil need frequent watering and fertilizing.
Clay soil retains moisture and nutrients, but is heavy and harder to dig than sandy soil. It warms slowly in the spring, drains slowly and contains little oxygen.
(Referred to as "Normal" in our Product Quick Facts Box)
Loam has a good balance of clay, sand, silt and organic matter particles. It drains well, but doesn't dry out too fast. It is rich in plant nutrients, is easy to dig and has plenty of air space.
What Type of Soil Do You Have?
To get a general idea of your soil type, take a handful of moist soil and squeeze it. Clay soil forms a tight ball that stays together when you tap it. Sandy soil doesn't form a ball and may run through your fingers. Loam holds together when you squeeze it but falls apart when you tap it.
For a detailed report on your soil, you can gather samples and have them tested by a soil testing laboratory. Many states offer this service through the county Cooperative Extension office. Go to http://www.csrees.usda.gov/Extension/index.html to find the office nearest you. There are also private labs that test soil. Test results will tell you the type of soil you have, the amount of organic matter it contains, the nutrient levels and pH. The report usually suggests materials to add to your soil to improve it based on what you want to grow.