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Garden Soil Testing: Know Your Backyard Dirt

Garden soil testing: two easy ways to know your backyard dirt.

Because not all dirt is created equal.

You want soil that drains well, yet retains enough moisture to keep the roots from drying out.

You want it to have a lot of organic matter for nutrients; yet you want dirt that does not compact; and does allow roots to spread easily.

Dirt is made up of three types of particles: sand (large), clay (small) and silt (medium). The optimum mix is 40 percent sand (for drainage), 40 percent silt (for nutrients and drainage) and 20 percent clay (for nutrients and to conserve water).

When soil has that precise mixture, it is called "loam". But how do you know what you have?

Try one of these two simple tests to find out.

1. The squeeze test.

• Squeeze a fistful of wet dirt and release.

• If it falls apart, your dirt is too sandy or silty.

• If it holds together in a ball, press on the ball. If it breaks apart easily, you've got the right combination.

• If the pressed ball sticks together in a hard lump, looks shiny and feels sticky, you've got too much clay.

2. The dissolving test.

This test involves soaking some dirt overnight in water.

• Dig up a small amount of soil.

• Put it in a quart jar (fill just under half full) and top it off with water almost to the rim.

• Shake until the soil is dissolved and let it sit overnight.
  

The next day, you will find three different colored layers in the jar. The heavy sand portion will be on the bottom, with silt in the middle and clay on the top.

There will also probably be some fine organic matter floating in the water. The more the merrier because the more organic matter, the more nutrient-filled your dirt.

You may, however, want to test your soil's pH level.

Most plants grow best in a neutral pH but some plants, such as rhododendron and azaleas, prefer acidic growing ground.

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About the Author

Tara Aronson is a native Californian. Having grown up in San Diego, she studied journalism and Spanish to pursue a career in newspaper writing. Tara, whose three children - Chris, Lyndsay, and Payne - are the light of her life, now lives and writes in Los Angeles. She also regularly appears on television news programs throughout the U.S.