Double digging. Doesn’t that term just make you break out in sweat at what it might entail?
I can tell you that it will make you break out in sweat before you’re done with it.
But I can also tell you that using this technique doubled my carrot yields. It gave me far superior roses over conventional soil systems and I can’t even begin to tell you what a major difference double digging made to my perennial beds. And yes, I did use this system on over one half acre of perennial garden beds. And yes, it took a long time but it was worth it.
Double digging is the old (we’re talking hundreds of years here) garden technique that is still as effective today as it was back in medieval Europe.
Do Yout Own Test
Let me suggest a simple test for you. Follow the directions below on a small bed. Grow a few flowers, a few vegetables, a few herbs in this bed next year. Grow exactly the same plants right beside them on a section of bed that you prepare as you’ve always done. Trial them! See which bed produces more. (try carrots if you want to be amazed!)
Double digging can be used for any size bed but I generally used a 3×8′ plot to make the project manageable and split the work into chunks I could manage in an hour or so.
How To Double Dig Your Garden
Dig a trench across the width of your garden bed. Dig this trench 18 inches deep and approximately one foot wide. The depth originally comes from “double the depth of a normal shovel’s blade – hence double-digging.
The soil from this trench can be tossed to the far end of the bed. This is why I limit the length of my working bed so I can easily toss the soil. If your easy toss is less than mine, then make your working bed shorter.
You now have a trench with a pile of dirt 6-8′ away. Congratulations!
Now you dig a second trench beside the first so you’ll have a two foot wide trench across your garden bed.
But I don’t want you to throw it to the end. I want you to fill the first trench in. As you dig the second to fill the first, you can remove all rocks, weed roots and any other flotsam or jetsam you find.
As I’m filling in my first trench, I also add compost and peat moss at the following ratio.
Add Compost and Peat Moss
For every 3 shovels full of original garden soil I move, I add a shovel of peat and a shovel of compost. So the digging rhythm goes – 3 shovels of soil, 1 shovel of peat, 1 shovel of compost. 3 shovels of soil, 1 peat, 1 compost.
- I don’t bother mixing them as the quantities are fine.
- I do try to spread the peat and compost over the soil so they look as mixed as possible.
I continue doing this until I have a second trench dug and the first trench filled in. The first trench is now full of a superb soil, it is well aerated, has no rocks or weeds, and is full of organic matter (peat and compost) a full 18” deep so new roots will have no trouble penetrating and finding nutrients.
You Can See The Next Step Coming
Once you’ve finished digging the second trench (and filling in the first) it is time to dig the third trench and fill in the second.
You continue doing this all the way down the garden bed until you get to the pile of soil. Use the pile of soil to fill in the last trench. (don’t forget the peat and compost)
If all has gone according to plan, you now have a series of filled-in trenches or a superbly dug garden bed. The level of this aerated garden bed will be higher than surrounding soil because of 1) the aeration and 2) the extra compost and peat you’ve added. Don’t worry about it, the bed will settle out in a week or two.
Don’t Let People Walk On It
Do not let people walk on this bed. Their weight will compact the soil and reduce all your work to a shadow of its potential.
Double digging is not for the faint of heart. It is garden work of a serious kind that produces healthy plants and serious yields.
How Often Do I Double Dig?
- I double dig the small kitchen/ fresh herb garden every year so I have outstanding fresh vegetables for summer use.
- The main vegetable garden would be double dug every three to five years. Or a few each year so the entire garden would be dug over every 5 years.
- The perennial beds would be double dug when being established or renovated. Then as plants would be moved around each spring, I would “double dig” the surrounding area as much as possible but not do the entire bed and disturb established plantings.
Why Is It Unpopular?
There are a group of folks who consider doing this “bad” for the soil because it cuts up and mixes the fungal strands that would normally develop. Some of these folks are getting their information from the compost tea school of gardening which says that fungal strands are important to good plant health.
What they seem to forget it that the same compost tea concepts say that fungal strands are important for woody plants (trees, shrubs) and not so much for flowers and vegetables. Flowers and vegetables do better when there are high levels of bacteria in the soil according to this gardening theory. (Yes, they do use fungal strands but not to the same extent.)
In my mind, double digging adds a great deal of bacterial food to the soil as well as creating a wonderfully aerated soil. I don’t worry about the fungal masses when I’m vegetable and flower gardening.
All I know is double digging works to give me amazing harvests of sweet tender vegetables (but yes, it’s a ton of work).
Is It Recommended?
Well, no it is no longer recommended by many garden experts (see above).
All I can tell you is that it works for me and has worked for me in improving dry sandy soil (my farm garden) as well as what passes for soil in my current garden (clay)
I’d suggest you run a small test yourself to see if it makes a difference to your garden. Dig up a four by four patch and see what happens in that area compared to the rest of your garden.
As an aside, it may be that I’m getting too set in my ways about this but… 😉