This simple project can help you determine the mineral composition of your lawn, measuring the levels of sand, silt and clay in your soil. You can understand what will grow best in your lawn or garden as well as determine what treatments or soil amendments you might use to achieve the healthiest property possible. The jar test I describe here takes very little manual labor, but it will enable you to be much more efficient and effective with your lawn and garden care since you will better understand the composition of your soil.
You will need:
Quart-sized jar with lid
Trowel
Plastic or paper bag
Newspaper
Teaspoon
Measuring cup
Calculator
Tape measure or ruler
Marker
Water
Powder dishwasher detergent
Instructions:
1. Gather a soil sample from around our yard. You only need about a cup of soil, but I suggest taking around ten small samples from around the yard to get a comprehensive look at your soil. To take each sample you will need to dig a hole about the size of your hand with the trowel. Scrap some soil off the side of the hole and place it in the bag. Repeat the process for each small soil sample.
2. Take the soil samples and pour them out onto a newspaper. Mix the soil together so that it makes one cohesive sample.
3. Allow the soil to dry completely and remove any organic debris, rocks, etc. Break up any remaining lumps of soil.
4. Put one cup of the collected soil into the quart sized jar.
5. Add two cups of water to the jar.
6. Add a teaspoon of powdered dishwasher detergent to the jar.
7. Seal the jar tightly and shake well. Shaking for around ten minutes will give the soil time to break down into its components: clay, silt and sand.
8. Place the jar somewhere that it will stay undisturbed.
9. Once the jar has sat for around one minute the sand from the soil will have settled to the bottom of the jar. Use your marker to mark the height of the sand.
10. After around two hours, the silt will have accumulated and settled on top of the sand. Mark the height of the silt with your marker.
11. Continue to leave the jar unattended until the water clears. This could take a few days, and sometimes up to a month. When the water has cleared, you will be able to see the layer of clay resting atop the silt layer. Mark the height of the clay with your marker.
12. Measure the height of each layer, as well as the total height of soil in the jar.
13. Use your measurements to calculate the competition of your soil. Divide the height of sand thickness by the total height of soil in the jar. Multiply the results by one hundred to determine the percentage of sand in your soil. Repeat the calculations, replacing the sand height with clay and then silt, to get comprehensive percentages of soil components. The idea composition is generally around 40 percent sand, 40 percent silt and 20 percent clay.