Double Digging

I used to be a proponent of rototilling. It was comparatively easy to hand digging new beds. Especially if you have clay soil.

When we moved into our house there were no beds. We wanted to make three 75′ long x 4′ wide beds. Seemed to be a rather daunting task to do by hand, so we rented a rototiller. It took a full day to do the beds with it.

So as it turns out we ended up having to hand dig the beds later on. After we rototilled it rained for several days and re-compacted the soil. When we dug it was just a shovel head deep and flipped the soil over.

If only I had known how much damage we had done to the soil! Throughout the growing season I noticed that there weren’t any worms! Before we started there were so many of them. Where did they all go?

Then I started researching gardening techniques. We used to use raised beds at our previous home. Unfortunately raised beds would be cost prohibitive for us. I needed to fix our soil!

As it turns out, rototilling creates a hardpan right under the turned soil by compacting it with the blades and then burnishing into a nice hard, shiny surface. This not only creates a barrier keeping worms out of the tilled soil, but it also reduces drainage and keeps roots for penetrating the soil deeply. Rototilling also created a horrendous weed problem for us. Our two worst weeds are Bindweed and Bermuda Grass. Both are perennials which easily propagate themselves through cut roots. Rototilling ended up cutting these roots up into small pieces and distributing them all through the beds. It also brought all the buried, dormant weed seeds up to the surface to germinate. Our weed problem was a neverending battle. A war we just couldn’t win.

Deeper soil means deeper roots which mean closer spacing. When the roots can’t go deep, the are forced to spread out, which causes too much competition between plants, requiring them to be spaced further apart.

The French Intensive Garden uses this rooting concept. Plants are tight together, and yet flourish. So how do you get the soil deep enough? And how deep is deep enough? Easy, Double Digging, which helps create deep, loose soil 2′ deep without destroying soil structure. This is essential to not only worms, but bacteria, fungi, and other beneficial organisms. It also helps keep buried weed seeds from coming to the surface. Double digging also allows me to pull out weed roots as I went along.

So how do you double dig?

You will need a round head shovel, a spading fork, two 5 gallon buckets (or wheel barrow), and a metal rake (not shown). The contractor style D-handle (on the spading fork) is preferred over the full length handle (on the shovel) because it will save your back. However, I don’t have a D-handle shovel. I do need to add a quick note about tools. Buy good quality tools! This is our second spading fork in a month. I ended up returning the first one because we broke the handle. It was a fiberglass handle and the company claimed it was stronger than all other fiberglass handles. I believe it even had a 15 year warranty. But it wasn’t nearly as strong as a wood handle – which is also more expensive. When choosing a wood handled tool definitely look closely at it and make sure there aren’t any knots or other defects in the wood. I was able to find only one without knots out of 5 on the racks and even this one is starting to show stress.

First determine where you want your bed. I recommend making a bed no more than 4′ wide because otherwise it can be difficult to reach the center without stepping on your nicely dug bed. You can mark it with stakes and string, construction marking paint, whatever you want. I don’t mark ours because they are existing beds that I’m working with. Add a 1″ layer of compost and 1″ layer of sand if you have clay soil. Then water it. Water it good. A sprinkler works better that drip. I water our soil for about 30 minutes. However, if it’s been raining a lot, you can skip this step.

Leave it alone overnight. This makes it so the soil isn’t a goopy mess and lightens up a bit but is still easily diggable. Because lets face it, no one wants to dig either hard dry clay or wet, sticky, HEAVY clay.

The following day you start digging. First start by making a trench about a shovel head deep and wide and put the dirt into 5 gallon buckets.

Once you have your trench dug, take your spading fork and start loosening up the soil at the bottom of the trench. Continue loosening until you can easily push the spading fork all the way in to the top of the tines all the way across the trench.

Now create a second trench moving the soil into the first trench. Don’t flip the soil, just move it. Loosen the soil at the bottom of the trench has before. Continue these procedures until you’ve gotten to the last trench. Then take your buckets of soil and dump those into the last trench. Rake the bed smooth. Don’t worry about any large dirt clods. If you water with sprinklers, or if it’s raining the clods will break down. Make sure to work backwards so you don’t recompact your now loose soil by standing/stepping on it.