I’ve written quite a bit on our efforts to restore the back yard, which, isn’t really a yard. As a recap, starting about 5 feet from the back door our property rises nearly 20 feet over a run of about 20 to 30 feet. You can see in the picture below the view across the first set of retaining walls that sit atop the rock outcropping.
This outcropping of the Salem Gabbro-Diorite creates a low ridge that emerges suddenly from otherwise level ground and runs about 500 feet or so parallel to our street before dipping back down. The formation is evident in a few of my neighbor’s yards, but is most pronounced in mine. Turning this outcropping into accessible ground has been a lot of work: removal of invasive species, replanting with native plants, terracing, building steps, etc. Challenging yet rewarding, and the work is ongoing.
Last year we terraced off a small section along the right hand edge of our property in order to put in a vegetable garden. The area had previously been overrun with invasive like multiflora rose and shaded by a Norway maple. After removing these invasive we were left with an area of marginal ground. The soil was relatively shallow (little more than a foot in spots), rocky, and lacking in substantial organic material. The terracing helped increase the soil depth a bit and I was able to introduce some organic material into the soil.
Our first year’s garden was moderately successful. Truth be told, I didn’t have very high expectations for year one, knowing how poor the conditions were. Our tomatoes did O.K., as did the squash. The beets really struggled, as did the eggplant. I suspect soil PH and nutrients were at issue. The soil was also pretty compacted in spots. Despite those struggles I was happy that anything grew given how poor the conditions were before we constructed the low retaining wall and started the process of reclaiming that small bit of land.
Nearly a year later, we were ready to move on to step two which was to construct raised beds. The goal was to buy ourselves a little more soil depth, increase soil fertility, and ameliorate the problem of soil compaction. In the early 2000s, I managed a community gardening program in Wilmington, DE run by the Delaware Center for Horticulture. The problems faced by the community gardeners I worked with in that urban environment were similar to what I am dealing with here: nutrient poor, highly compacted soils. In Wilmington we had bricks and concrete in soil whereas here I have rock. About the only thing I’m not dealing with–thankfully–is soil pollution (Wilmington had elevated levels of lead and arsenic). Our solution there was also to build raised beds.
There is nothing complex about building raised beds. The only real question is the type of material you want to use. Obviously the fact that there is soil contact means that natural materials will eventually decompose and need to be periodically replaced. Pressure treated lumber is less toxic than it used to be since it no longer contains arsenic–nevertheless, I didn’t want to use PT lumber in my veggie garden. Cedar is rot resistant as is cypress but both were cost prohibitive. I also considered Douglass fir, though that ain’t cheap either. As this is a project on a budget (I have a Disney vacation to pay for) I simply used pine 2 x 8. I expect I’ll get no more than three or four years out of it before I need to rebuild. In the meantime. I am going to work on sourcing recycled plastic timbers like I used in Wilmington or perhaps I’ll find a source for cypress.
The beds were assembled with simple butt joints fastened with decking screw. I drove some stakes into the ground to stabilize the frames. I filled the beds with compost, peat , and a bit of vermiculite. That’s it. Easy. We are going to use square foot gardening to maximize out limited space–another technique that I learned doing community gardening.
We are approaching mid spring and have already planted carrots, radishes, spinach, lettuce, and onions. Elsie was if course in on the action.
As she planted she was humming and singing this great old song. I’ll post more as the gardening season progresses.