Test the composition of soil yourself

Through a soil analysis at each area where you will be planting, you can determine at home the breakdown of sand, silt, and clay in the soil to determine if you need to adjust the soil composition. Sand drains well, while silt and clay retain water. 

Supplies

To perform a simple soil test at home, you will need a ruler and a small, empty, clean glass jar with straight sides and twist on cap, like a pickle, applesauce, or jam jar.

Steps
  1.  Fill the jar 1/2 full with soil. Add tap water on top of the soil until the jar is 3/4 filled. The soil will soak in the water.
  2. Twist on the cap and then shake the jar for at least one minute (longer, if you see chunks) to thoroughly breakdown the dirt so what you are seeing is a murky, muddy fluid. Set the jar aside for two days, without touching it, to allow the contents to settle.
  3. After two days, you will see three layers in the jar. If you need to move the jar to view it more clearly, move it very carefully so as not to disturb the settled contents (sediment). The bottom layer in the jar is the sand content; the middle layer is silt; and the top layer is clay.

Calculate

To calculate your soil composition, figure out what percentage each layer of sediment is over the whole. Measure from the bottom of the jar to the top of the clay soil level (top level). Then measure the height of each individual layer.

In the example pictured above, I measured to the nearest 1/4 inch. The total height of all three layers is 1 1/2 inches with a breakdown of clay = 1/4 inch, silt = 1/2 inch, and sand = 3/4 inch. That means that 50% of this soil sample is sand (.75/1.5*100), silt is 33% (.5/1.5*100), and clay is 17 % (.25/1.5*100). Since sand drains well and this soil sample is half sand, it should drain well making it suitable for plants that do not like to keep their roots wet.
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