The soil that's darkest in color is widely known as topsoil. Soil scientists call this layer the "A-horizon." It's the "black, organic, rich soil that's really good for growing crops," says Evan ...

Soil scientists, and anyone who enjoys digging deep (which I highly recommend), knows that soil consists of layers, or horizons. The layers vary in depth and composition, depending on where the ...

O horizon: This is the top layer of soil that is made up of living and decomposed materials like leaves, plants, and bugs. This layer is very thin and is usually pretty dark.

The basic premise of double digging is to create an extra deep bed of loose soil – 16 to 18 inches, versus the 6 to 8 inches that most tillers create – without inverting the soil layers. In the ...

A spodosol has a gray horizon from which acids have leached nutrients, depositing it in the reddish horizon below. Photo by Audrey Clark. Editor’s note: Landscape Confidential is an occasional ...

The cores provide pictures of thousands of unique soil "horizons," Hatten said -- layers of soil showing different characteristics based on age and composition.