Mason Jar Soil Test

Jessie Clark, Master Gardener Trainee

A Mason Jar Soil Test is an easy way to learn your soil composition (ratio of clay, silt and sand) which can inform the water and fertilization needs in your yard. The ideal soil composition is referred to as Loam, with a ratio of 40% sand, 40% silt, 20% clay. If you find that your soil composition is far from that, some would recommend supplementing your soil, and others would suggest that your soil will likely continue to go back to its natural composition, meaning it would simply be wise to landscape with plants that thrive in the conditions you already have. Knowing more about the soil we already have can help us better understand the watering and fertilization needs to keep our plants healthy, and help inform your landscape plan for 2020.

Materials Required:

- Large Mason Jar with Lid (I used a 32 oz.)

- Small Shovel

- Water (I used the faucet)

- Measuring Tape

- Pen & Paper


1. Gather materials.

2. Shovel some soil from the ground and fill your mason jar half way. Be sure to avoid breaking any tree roots.

3. Fill the other half of the mason jar with water.

4. Put the lid on tight, and then shake it very well (blending the soil and water). When I did this experiment, the water drained through the soil and left much room in the jar on top. So I topped it off with water and shook it again.

5. Set the mason jar on a flat surface for the soil to settle. The top half (the water) will be a bit murky looking and will contain some organic matter. After some time passes, soil will rest on the bottom and after a few hours will separate into clay, silt and sand.

6. Once soil has completely settled, measure the total amount soil. Then separately measure each type of soil. Divide the soil type by total amount of soil and multiply by 100. This gives you the soil composition!

Our yard was 6% clay, 60% silt, and 33% sand. Here’s an example of how to calculate:

0.2" clay (.2 / 3 x 100 = 6%)

1.8" silt (1.8 / 3 x 100 = 60%)

1.0" sand (1.0 / 3 x 100 = 33%)

Interested in learning more about your soil? You can send a soil sample to the Soil, Water & Forage Testing Lab with Texas A&M AgriLife Extension Services to get a report back. The sample bag and form to be completed can be obtained at your local extension office, and more information can be found at http://soiltesting.tamu.edu.


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