Happy Earth Day

For Earth Day this year, take some time to appreciate the rich soil that covers our planet and supports plant life. Try this soil seed-bank test to discover the magic of topsoil.

Earth Day Terrarrium - Beginning Growth

The soil seed-bank test is used by farmers, scientists, and others to find out what weed seeds are hidden in a garden or cropland’s soil that could affect the growth of the crop. You can use the same basic procedure to find out what is living in the soil in your yard or other location. For this variation of the test, your objective is to study the materials that emerge without judging the value of the plants. Weeds are just plants growing where we don’t want them, and you definitely want everything to grow in your seed bank.

The basic directions for a soil seed bank are very simple: dig up a cup of soil, place it in a container, place in a warm location, keep it moist, and watch to see what grows. That’s it!

If you want to be more elaborate, you can make a terrarium of local plants. Here’s how I turned the soil seed-bank concept into an awesome forest floor terrarium.



  • 10-gallon fish tank with top
  • Pea gravel (I used ceramic gravel.)
  • Mesh fabric (You could also use cotton fabric or paper towels.)
  • Coconut fiber like Eco-Earth pet bedding (Potting soil would also work.)
  • About 4-6 cups of soil from a woodland area
  • Dry leaves (leaf litter) from the ground above the soil collection site
  • Moss growing nearby


  1. Pour a layer of gravel about 2 inches deep on the bottom of the terrarium. This will collect excess water and keep the soil moist.
  2. Cover the gravel with a sheet of fabric to prevent the next layers from filling spaces between the gravel. You want that air space.
  3. Cover the fabric with a layer of moistened coconut fiber or potting soil, about an inch deep.
  4. Spread your forest soil over the “artificial” soil layer; place moss and leaves on top.
  5. Water the terrarium and put the lid on to keep it humid. Place in a warm location and watch what happens.


Earth Day Terrarrium - Beginning Growth

In the beginning, it will look something like this.

Earth Day Terrarrium - Beginning Growth

In a very short time, grasses, sedges and other plants begin to grow.

Earth Day Terrarrium - Beginning Growth

The plants eventually grew so tall I had to remove the terrarrium lid.


If you love forests as much as I do, you will want to lift the lid every day to greet the emerging seedlings and catch the distinct aroma of fresh earth. This is the time to appreciate the value of topsoil. This rich material that has formed over a very long time on our planet sustains us and all of the creatures on land. We need to take care of soil, water, and air to preserve the health of the earth.