A Guide to Raised Bed Gardening
Gardening in Raised Beds Needn’t Involve Buying Raised Bed Kits, But it Does Require Planning
Raised bed gardening is the ideal solution for overcoming both poor soil conditions and seasonal weather. Beds constructed on top of the ground may be filled with the garden soil mix of your choice. And you can work in your raised beds when wet conditions in a conventional garden would result in soil compaction.
Raised Bed Gardening Versus Structured Beds
For some gardeners, raised bed gardening means mounding rows of soil with dirt paths between them. That may work okay for crops that are mechanically maintained, but it isn’t ideal in a backyard garden.
For one thing, reshaping beds year after year entails a lot of work, which often can’t be done in a timely manner when spring weather keeps the soil wet. Even when the weather is conducive to shaping beds for early planting, a heavy spring rain may erode them back down flat. And anyone working mounded soil beds has a tendency to step off the path and trample the soil.
A permanent, or structured, bed is essentially a big box filled with soil. Constructing one is initially more time consuming than building a mounded row of the same size, but it’s a one-shot deal. Once the bed is built and filled with raised garden soil mix, it’s pretty much ready for planting year after year.
You don’t have to build all your beds at once, either. You can start small and add beds as time and materials allow. And — as is the case in our garden — as the availability of soil allows. Since we garden on rocky clay soil, we sift all our soil and mix it with compost before using it to fill a new bed.
Advantages of Raised Bed Gardening
Compared to mounded beds, structured beds can have better, deeper soil for stronger roots and more productive plants. And where the terrain is hilly, terracing the beds provides level ground to plant in.
Another advantage of raised beds is that they make gardening easier on the back, because you needn’t to bend over as far to harvest or weed. Less weeding is involved, because the vegetables are confined to limited and specific areas of the garden. And the beds require less water for irrigation because the paths between the beds don’t get watered. Not applying water to the paths keeps them free of mud and weeds.
The typical structured bed is 4-feet wide, allowing the gardener to work from either side without having to step onto soil to reach the middle. Footprints compact the soil, decreasing its capacity to hold both water and oxygen, and damaging the soil structure, including the structure established by old roots and delicate microbial webs.
Not walking on the soil means it needn’t be tilled. And that’s a good thing, because tilling is as detrimental to soil as the compaction caused by stepping in it. The same aspects of soil life and structure that are disrupted by compaction are disrupted by tilling.
To maintain the life and structure of our soil, we sow a ground cover on each bed for the winter. In spring we top off each bed with well-composted bedding gleaned from our barn stalls, which makes the best compost for garden use.
Constructing Structured Beds
In developing our raised bed garden plan, we made most of our beds 4-foot wide and about 30 feet long. But we also included some large square beds, which we use for growing pumpkins and growing sweet potatoes, that would sprawl into paths between narrower beds.
We chose to design our own structured beds, rather than buying raised bed kits, for several reasons. Kits are more expensive, yet are generally smaller and have less soil depth than is possible with homemade beds. Although ideal minimum soil depth is about 12 inches, most of our beds are 22 inches deep.
Initially, we constructed our beds by laying concrete blocks on top of concrete footers. That produced as permanent a structure as we could hope for, as well as nice solid walls to sit on while weeding or harvesting.
As time went by and our garden grew, constructing block beds got to be a bit much for a pair of not-so-young gardeners, so our more recent beds are constructed of composite decking screwed to upright posts set in concrete. These beds look nicer than the block beds, and the decking takes up less growing space than blocks.
Another change we made as we went along involved the paths between the beds. Initially our paths consisted of compacted soil, but we soon learned that weeds take advantage of moisture seeping along the edges of the beds.
Now we cover our paths with about 4 inches of gravel screenings, which are fine gravel particles interlaced with gravel dust. As we spread the screenings, we pound them with a dirt tamper to make them nice and compact. The resulting path is nearly as hard as concrete, but drains well.
In aiming for self-sufficiency, our initial goal was to construct 175 feet of 4-foot wide beds per person, which provides plenty of produce to both eat fresh and can for winter. Beyond that amount, additional beds simplify crop rotation, as well as providing surplus produce for our appreciative backyard chickens and dairy goats.