This Saturday workday our group got two beds ready for planting! Tree gave us a tutorial on how to prepare them by double digging.
Step 1.) Your beds should have a 4-6" layer of compost on top to start with.
Step 2.) See Tree there in the photo below with the shovel in as deep as the shovel's head? That's as far down as you want to dig. You also only need a width of one shovel's head.
Step 3.) The soil from the first trench should be placed in a wheel barrow. That soil goes to the far end of the bed where it will be used to fill in the last trench.
Step 4.) Stick a digging fork in the trench you just dug so the tongs are fully submerged. Wiggle the fork around to loosen up the soil. This wiggling aerates the soil allowing roots more space and increasing drainage.
Step 5.) Now that the soil in the first trench has been loosened up you can begin digging the second trench right beside the first; same depth, same width. The soil from the second trench (including the 4-6" of compost on top) gets put into the first trench. You're just moving dirt from hole #2 into hole #1. Easy as that.
Just keep following this pattern of digging out a trench, working the fork into the dug-out space and then digging another trench right beside it and putting the second trench's dirt into the first. Do this all the way down the line. Mixing nutrient rich compost in with your soil helps build the soil structure, making the beds a hospitable area for food growing.
After raking the beds even our beds look like this.