How to Test Soil Composition


Soil is composed of sand, silt, clay, organic matter, air and water. Different soils contain different proportions of these materials. Sandy soil has a lot of air but little water and organic materials, while clay soil has more water and little air, but plenty of minerals.

Step 1

Scoop a cup of soil from your yard. Place it in a large jar and place a tablespoon of powder dish detergent on top of it.

Step 2

Fill the jar with water, put on the lid, and shake it for at least three minutes until everything is combined.

Step 3

Set the jar on a flat surface and wait one to three days until the soil in the jar settles.

Step 4

Measure each layer of soil in the jar. Organic material will be floating on top of the water. Clay will be the top layer, silt the middle layer and sand on the bottom layer. If each layer is of relatively equal parts, you have loam--about 30 percent clay and 50 percent sand and silt. If any one part of the soil is significantly greater than the others, such as 50 percent clay or 80 percent sand, your soil is either clay-like or sandy.

Things You'll Need

  • Large jar
  • Powder dish detergent
  • Water
  • Ruler


  • Dummies: How to Assess Soil Composition
  • Fine Gardening: How's Your Soil Texture?
Keywords: soil composition test, testing soil composition, soil composition

About this Author

Hollan Johnson is a freelance writer for many online publications including Garden Guides and eHow. She is also a contributing editor for Brighthub. She has been writing freelance since 2008 and her interests are travel, gardening, sewing, and Mac computers. Prior to freelance writing, Johnson taught English in Japan. Johnson has a Bachelor of Arts in linguistics from the University of Las Vegas, Nevada.