When it comes to home gardening, we’ve probably hit “peak raised beds.” It seems almost everyone (except those stubborn old-fashioned farmers) has ditched row gardening and big spaces for tight little controlled boxes of heavily irrigated plants in perfect soil.
This isn’t necessarily a bad thing, especially considering how many people live in tight spaces without access to heavy equipment and lots of ground.
However, it’s also not the only way to grow crops in a small space. There’s another way that’s cheaper… requires almost nothing in terms of materials… and can yield a highly productive 5′ x 8′ bed in a couple of hours (if you have a good back.)
What is this magical Third Way? Double-dug “biointensive” gardening, baby. Get ready to bust some sod.
The complete biointensive approach is perfect for getting a productive garden going on the cheap. In fact, it’s been used in Kenya and elsewhere for that very reason. Based on the pioneering work of English master gardener Alan Chadwick and improved upon by John Jeavons, this method relies on double-digging, compost, and close planting of veggies to keep the soil loose, fertile and moist. John Jeavons’ book “Grow More Vegetables” is a wealth of information on this method. However, you don’t have to buy into the whole biointensive thing in order to learn a lot from it. Some of its tenets, like super-close spacing, frequent watering and novel approaches to spacing and fertilization are not part of my routine. But there is one aspect that really, really impressed me when I tested it out… and that was double-digging. If – like me – you don’t go all the way into the biointensive thing – at least take this truth away: double-digging is powerful stuff.
Why Double-digging Works
When we look at our garden plants, we tend to think about only what we see. If the growth above ground is green and happy, great! Unfortunately – that’s only half the picture. Root growth is really, really important to the health of a plant and its ability to stand drought stress, find nutrients and keep itself supported. When you use a tiller, you’re really only ripping up the top 6” or so of the ground. Beneath that, the soil might remain hard and unyielding to plant roots. The deep mulch method (also known as lasagna gardening or the “Ruth Stout” method) can loosen soil over time by attracting worms that aerate for you – but if you really want to get your gardens going in a hurry, double-digging is the way to put food on the table ASAP. It also doesn’t require you to find great big piles of organic matter.
Did you realize that some veggie roots will penetrate as deeply into the ground as you are tall? You’d never know when you yank up a little plant, but the complete collection of its roots were much more impressive than just what you see. Loosen the soil deeply and much more water and nutrients become available to the ever-searching (and sometimes microscopic) roots of your veggies. Plus, having air in the soil is a good thing – roots need to breathe as well.
With moderate watering and weeding, double-dug gardens do very well. I was quite pleased with the results; especially since I wasn’t sure how well double-digging would work in my sandy yard. Six months after I dug my initial double-dug beds and three months after I harvested them, the soil, though weedy, was still fluffy and loose. A year later… and they were still softer than the surrounding ground. A bit of weeding and raking and I planted them again. Now that we’ve taken a look at why double-digging works… let’s look at how you do it.
How to Double-Dig
Haven’t double-dug before? Well, you’re in for a good workout. To do it, first attack and remove the weeds from a patch of ground. I usually shoot for a space at least five feet wide and as long as is convenient. Carefully toss aside nutsedge roots, rocks, old boots, beer cans and other debris.
Then, make a foot-deep trench across your prospective bed’s width and put the dirt in buckets or in a wheelbarrow. Then loosen the dirt in the bottom of that trench with a spading fork (double-digging is the reason why I count the spading fork as one of my indispensable tools) or turn it over with your shovel to the depth of another 12” or so. After that, dig up the adjoining strip of virgin ground and turn it into the first trench as you go, continuing to dig and loosen to a depth of 24” all the way until you get to the last row. At that last row, dump in the extra dirt from the first one and— voila! – you have a beautiful loose patch of soil, all ready for seeds or transplants. If you want to add compost (which is always a good idea) or well-rotted manure, do so by pitching some into each trench before covering with soil from the next strip.
Does this sound complicated? Perhaps seeing it done will help – take a few minutes and watch this video from John Jeavons.
With proper double-digging, the patch ends up about 6” higher than the ground around it. The fluffiness and tilth beats the living daylights out of anything you can do with a rototiller. After this work, don’t step on it! Avoiding soil compaction is key to higher yields. When roots grow easily, plants thrive. Though the folks in the video say it doesn’t really take hard work… that’s going to depend on your soil and your level of fitness. I can double-dig almost three times as fast as my wife. But I attack it like the world is about to end – because it probably is – whereas she moves slowly and gracefully, like the people in the video. There are also places in the country where double-digging is basically impossible, such as in the rocky red clay across the mountains of Appalachia, or the lime-rock ground in the Florida Keys.