Double digging garden soil is a practice that goes back hundreds of years. Gardeners with limited gardening space developed many ways to increase their yields of crops. Double digging the soil in a garden bed is one of those ways.
Essentially, you dig down twice the depth of a garden spade, set aside the removed soil, and loosen the soil at the bottom of the trench. You then replace the soil, removing rocks and adding soil amendments such as peat moss, compost and manure.
Sure, it sounds like a lot of work because it is a lot of work. But the increased yields you reap are phenomenal. Really. If you doubt it, double dig a small portion of your garden. Plant a selection of herbs, flowers and vegetables in that area. Plant the same crops in a nearby area that you did not double dig. Compare the yields and health of the plants. Their health, vigor and increased yield will speak for themselves.
One way to double dig your garden soil is to do it in stages. The very nature of double digging makes this easy to do. Double dig one or two trenches, take a break and then resume digging.
Here’s the instructions for double digging a garden bed:
- Place a wheelbarrow near the spot where you will begin digging. Mark out a trench about a foot wide the full width of your garden bed (it doesn’t have to be exact).
- Using your garden spade, dig out the trench to twice the depth of the spade (about 18 inches) and place the soil you remove into the wheelbarrow.
- Using a pitchfork or regular garden fork, loosen the soil at the bottom of the trench. Stab the ground with the pitchfork and wiggle it back and forth until the soil at the bottom of the trench is loosened.
- Mark off a second trench the same size as the first one. Dig down about 18 inches (just like before), but this time put the removed soil into the first trench you dug. Add peat moss, compost, and manure (if you have it) in the following ratio: 3 to 4 shovels full of garden soil, 1 shovel full of peat moss, 1 shovel full of compost and 1/2 shovel full of well-rotted manure. Stop every once in awhile and mix them together with the spade.
- Remove any large rocks at the same time that you’re moving the garden soil from the second trench into the already-dug first trench. If you want to be really thorough, sift out any rocks with a soil sifter fitted with a screen with 1/2 inch holes.
- Continue working in this manner, digging out a one foot wide trench and putting the dirt into the previously dug trench. Don’t forget to loosen the soil in the just-dug trench before replacing the soil and its amendments from the newly-dug trench right next to it.
- When you reach the last trench, replace its soil with the soil you dug out of the first trench and placed into the wheelbarrow.
This last point is the most important: Do not walk on soil that has been double dug. It will compact the soil and negate many of the benefits that your hard work has produced.
It is recommended that you double dig the soil in vegetable gardens every 5 years.
Relax, it’s much easier the second time around, especially if you don’t ever walk on the growing area.
Copyright Sharon Sweeny, 2009. All rights reserved.