One of the most popular home tests for measuring the percentage of sand, silt, and clay involves nothing more sophisticated than a quart or litre glass jar with lid and a ruler. It is based on the rate these different particle types settle in water. The large, boulder shaped sand particles settle the fastest, followed by the smaller particles of silt, and then followed by the very small and flattened particles of clay.
Collect about 2 cups (500 ml) of soil to be tested and pick out the bulk of the organic matter. Let the sample dry in the sun and break up any clumps by tapping with a hammer. Put about 3/4 cup (200 ml) of the soil sample into the glass jar, fill almost to the top with water, cap the jar and shake vigorously for five minutes.
Let the jar sit undisturbed for 24 hours and measure the depth of the settled soil with the ruler. This is the total amount of soil particles. Shake the jar again for an additional 5 minutes and allow it to stand for 40 seconds. Measure the settled soil. This is the amount of sand in the sample.
Keep the jar undisturbed and measure the settled soil at the end of 30 minutes. This is the amount of sand and silt together. Subtract the amount of sand from that total for the amount of silt. Subtract the amount of sand and silt together from the total amount of soil particles to obtain the amount of clay.
Percentage of sand = (depth of sand/total depth) * 100
Percentage of silt = (depth of silt/total depth) * 100
Percentage of clay = (depth of clay/total depth) * 100