Clay soil is commonly referred to as heavy soil, because it has poor draining abilities that often results in plants getting fungal infections or dying from excessive water. This soil type is made up of other soils such as loam, sand and silt, as well as minerals, air and water. In order for a soil to be deemed clay soil, it must contain at least 50 percent clay. For gardeners, this can mean the death toll for a number of plants without making the proper soil amendments to improve drainage.
Fill a jar with 2/3 water. You can use an empty mayonnaise jar for the clay soil test.
Dig a 6-inch hole and collect 2 cups of soil from the bottom. Pour the soil into the jar.
Shake up the jar and allow the soil to settle for one minute. With a marker, mark on the jar where the first bottom layer of soil has settled. Wait two minutes and mark where the second layer from the bottom settles.
Allow the rest of the soil to settle for 24 hours. Mark on the jar where the top layer has settled.
Examine the soil layers. If the bottom layer makes up the highest percentage of soil in the jar, you have sandy soil. A high percentage of the top layer of soil indicates that you have clay soil. Three equal layers indicates loam soil, which has the best draining abilities.