Double digging

By Melanie Mathieson
Gardening Guru

Double digging is a technique used by gardeners when they need to work their garden soil deeper than traditional methods such as regular digging, cultivating or tilling. Although double digging is hard laborious work, it is very effective in assisting you in upgrading the soil. The efforts are well worth the results and often you only have to complete this exercise one time in your garden.
The purpose of double digging is to improve the quality of your soil by improving drainage and aeration. The process of double digging also allows you to add organic matter and have it work into the soil much easier. As with any digging, do not double dig when the soil is wet or bone dry. The soil should be fresh and slightly moist when you do this. You can use this technique on an established garden or when starting a new bed or choose to just do a portion of the garden.
To get started, mark off the area that you plan to work in. This is especially important when starting a new bed.
Start at the one end and edge of the bed. You will dig a trench right across the entire width of the garden. Dig the trench one foot wide and the depth of your shovel (the metal part only). When digging this soil in the first trench, remove it from the garden and put it into a wheelbarrow, garden cart or pails.
When you have completed the trench, work back across the bottom of a trench by digging and loosening the remaining soil within the trench to the depth of your tool (tiller, shovel or garden fork). If you have a tiller you can also use it in the trench. In order to achieve the most benefits from this method, compost must be added. It can be added at this stage or later on. After the soil is loosened you can add compost, organic material or fertilizer on top of the loosened soil within each trench. Tip: you can add leaves or other organic materials, that haven’t fully broken down yet, directly into the trench at this time. This is best done in the fall so you don’t dig it up when planting.
The next step is to create a second trench right next to the one you just dug. When excavating the soil from trench #2 add the excess soil into the empty area of trench #1. Continue step #3 right across the entire area you plan to work.
When you reach the last trench, use the soil from the trench #1 that you have saved in the wheelbarrow to fill in the last trench.
If you chose not to add compost to the trench then it is imperative that you add some compost or other organic materials to the surface of the garden after you finished digging. Apply your organic material liberally across the garden and work into the first 4-6 inches of the soil. The addition of the organic material is the key to the success of this exercise because it improves the quality of the soil and keeps it loose after you have done all of this hard work. You can use peat moss, well rotted manure, leaves and other plant material, etc.
You will notice that once you are finished, the height of your garden soil has risen a bit because of the addition of the organic matter and the fact that you have loosened the soil. The biggest reward will come when you plant it the next season and you will see how well your garden grows as a result.