What is double digging?

Double-digging is a preparation technique to loosen and enhance soil before planting. First, a top layer of soil is removed. Next, a second layer of soil is loosed. Both of these layers are the depth of a spade shovel. Finally, the first layer is mixed with additions and returned.

Additions to the first layer of soil can include compost, fertilizers or other nutrients. Loosening up the second layer of soil helps the roots of plants penetrate through. This technique also creates better aeration, providing better air and water flow for the plants. Although the labor is intensive, double-digging is most commonly done with a spade shovel and manual labor.