garden soil testing: know your backyard dirt

Not all dirt is created equal. Garden soil testing you can do yourself is the great equalizer: Once you know exactly what you're working with, you'll find your gardening success is greatly enhanced.

You want top 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 yet 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?  Here's how to do garden soil testing to find out.

  1.  The Squeeze Test

How to do a soil test:

• Squeeze a fistful of wet dirt and release.

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

  2.  The Dissolving Test

This soil sample test involves soaking some dirt overnight in water.

• Dig up a small amount of topsoil from your garden.

• Put the soil 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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