In our illustration of the ideal garden soil, we saw that half of the volume of the soil should consist of pore spaces. Half of these or 25% of the total soil, should be air spaces while 25% of the total should be for water. In a typical backyard soil, compaction over the years has squeezed down these pore spaces to where they may comprise only a very small percentage of the volume. The task now is to restore these pore spaces before we plant our new beds and borders.

For several centuries, the mould board plow has been used by farmers to turn the soil over every spring. This process did two things. One, it incorporated the leftover corn stalks or wheat stubble into the soil to add precious organic matter. The second thing tilling did was to incorporate air into the soil. After the plow passed through, the soil stood several inches taller than before due to the added pore space.

Farmers and vegetable gardeners can rejuvenate their soils every spring before planting a new crop. We perennial gardeners cannot do so and must be sure that we do a great job prior to our original planting. Adjusting the soil in a perennial bed after the plants are in is a very difficult task, indeed.

Whatever technique you use to till your beds and borders, it needs to work the soil down to the depth of the topsoil at a minimum. That depth may vary from site to site but will be around 8 to 10 inches in most cases. This may be done by hand digging with a shovel or mechanically turning the soil with a rototiller. It is also the time to incorporate organic matter as discussed in the following section of this eBook.

A time honored (and back-breaking...just kidding) technique for preparing ornamental beds and borders is called double digging. In this process, you dig a trench to the depth of the topsoil at one end of the bed and place the soil from the trench into a wheelbarrow. You then turn or stir the soil in place at the bottom of the trench to a similar depth. This will loosen the subsoil to help improve drainage.

Then, you move over a foot or so and dig the second trench using that soil to fill the first trench. Follow that by loosening the subsoil with your shovel or spading fork. Move to the third trench and so on until you arrive at the other end of the bed or border. There you will end with an empty trench. That is where you place the soil that you put into the wheelbarrow back at the first trench. At each step, you will be incorporating the organic matter into the topsoil layer only.