Double digging is a gardening practice in which the soil is worked deep down. This promotes excellent drainage and the development of strong, healthy crops and plants. Plants tend to be healthier in a double dug bed, and crops will often have an increased yield. Double digging is a lot of work, but some gardeners feel that the effort is worth it in the long run, especially if they work in small areas of the garden at a time so that they do not become overwhelmed with the task.
The “double” in “double digging” refers to the idea that the digging is down to two shovel-depths down, rather than just one, as is more conventional. This task needs to be done when the soil is moist, but not wet, and definitely not when the soil is dry. Gardeners start by digging a trench and emptying the soil into a wheelbarrow. Then, they loosen the soil at the bottom of the trench with a pitchfork or with more digging. Some gardeners also add soil amendments such as well-finished compost.
Next, a trench is dug beside the original trench, with the soil from the new trench going into the first trench. As soil is transferred, materials like rocks can be removed and set aside. The soil in the bottom of that trench is worked, another trench is dug beside it, and so forth. Gardeners can repeat this process until they have dug out the area they want, emptying the soil from the first trench into the last trench.
Double digging loosens the soil, offers an opportunity to introduce soil amendments to condition it, and allows gardeners to pull out rocks and other objects which can interfere with the health of plants in the bed. A double dug bed usually continues to be productive for several growing seasons, allowing people to take some time off before redoing the bed.
One important thing to be aware of with double digging is that walking on the beds compacts the soil and undoes much of the good work. People should be reminded to stay out of beds which have been prepared with double digging, and gardeners should make sure that garden paths are wide enough for people, garden trolleys, wheelbarrows, and so forth to pass freely between the beds. It's also important to avoid placing heavy objects in a double dug bed; things like sacks of mulch should be placed in a garden path while they are in use so that they do not compress the soil in a double dug bed.
