Getting the Dirt on Dirt

Have you ever stopped to think about what dirt is made of? If you haven’t, you will be surprised to know that all dirt is not alike.

Quick Navigation

The 4 basic types of soil:

Sand – Sand is made of tiny particles of dirt and rocks. Sandy soil is coarse and gritty. Sandy soil is the best soil to use for plants that do not need or want a lot of water—plants like cactus and succulents. Sandy soil also pulls water extra water away from a plant so that the roots do not become too wet. Geraniums and grapes are two plants that like sandy soil. They need to be watered regularly, but only a little bit at a time.

Clay – Clay is dirt that is usually reddish-brown in color and made from crushed rock. When clay is dry, it feels like powder running through your fingers. But when wet, it lumps together really tight…like clay. Clay is not good for growing plants because water makes it clump together instead of watering the plants AND the clay is so thick roots can’t grow very well. but is useful for making bricks and pottery.

Silt – Silt is a mix of clay and sand. It is powdery when dry like sand and clay, but it doesn’t lump together like clay does when it’s wet. Silt lets plants get just the right amount of water, but silt doesn’t have the vitamins and minerals plants need to be really healthy.

Loam – Loam is a combination of sand, clay, and silt. Loam is also loose and airy so that water and fertilizer have no problem getting to the plant’s roots. Loam is the best type of soil for growing almost all kinds of plants.

So what kind of soil do you have in your garden?

Do you and your family grow your own vegetables? Does your mom have a flower garden? What kind of soil are you growing things in?

Here is what you need:

  • A quart-sized clear glass jar with a lid
  • Water
  • Soil out of your yard or garden

Here is what you do

  • Fill the jar half-full of dirt.
  • Fill the remainder of the jar with water—leaving 1 to 2 inches of space at the top of the jar.
  • Shake the jar up and down for 30 seconds to 1 minute to mix the dirt and water well.
  • Set the jar on a table and leave it alone for 2 to 3 hours.

Here is what happens:

The dirt is going to separate into layers all by itself

  • The bottom layer will be the rock and sand particles because they are the heaviest.
  • The next layer will be silt. Silt is made from tiny particles of minerals.
  • The clay particles will be the top layer of the dirt in the jar. Clay packs together to make a thick lump, but it is really very light-weight.

Now what

Once you know what kind of soil you have, answer these questions:

  • What kind of plants will grow best in your soil?
  • What can you do to your soil to make it more plant-friendly?
  • Help your soil by adding earthworms and compost. NOTE: Compost is dead leaves, fruit and vegetable peelings, coffee and tea grounds, and eggshells.

You can also…

Once you know what kind of soil you have, answer these questions:

  • Take a new soil sample about 3 months after adding earthworms and/or compost to the soil. How has it changed?
  • Take soil samples from other parts of your yard. Are they different or the same?
  • Take soil samples from other places in your community. How are they different from the soil in your yard? NOTE: Get permission first.