Urban Farming Toolkit: Building a Raised Bed — Part 2
I’m working on my latest garden project — installing a raised vegetable bed. In Part 1 of this series I walked through the preparatory steps, which included: 1) Selecting a space, 2) Selecting materials, and 3) Gathering supplies. Here I continue with the second phase of the project — hands-on building:
Step 4. Prepare the space. Because I’ve been using our space to grow veggies for several years, and I’ve been amending the soil each year, the ground is in decent shape. So now I just need to dig a trench around the border as a foundation for the stones. The stones we’ve chosen are 8″ deep and 6″ high, so I dig a trench wider and deeper than that. I’ve used a hand cultivator, a trowel and a hoe for this step.
Getting the trench started with a hand cultivator.
Finishing the trench with a hoe. The deeper I dig, the more I can see the red clay in our Virginia soil. This is why I’m building a raised bed!
Step 5: Lay the foundation. As my good friend and wall-building-expert Mariano repeatedly tells me, this is THE MOST IMPORTANT STEP. The foundation will set the course for the rest of the wall, so we take our time with this one. First we put down gravel. (I didn’t know we needed gravel, so I hadn’t bought any — fortunately we have a million rocks in our backyard thanks to a bad landscaping decision years ago, so I happily shovel some of them into the trench).
Then we layer in paver sand to fill the gaps.
Next we begin putting down the base layer of stones. Leveling is critical for this stage, so we measure every side of every stone, and tap it into place with a rubber mallet until it’s exactly level.
Side note: It’s important to have the right tools for the job. Here’s the level I own, and the level Mariano brought for the job (he actually brought three different sizes). I love Mariano!
Step 6: Finish the wall. Now that we have a good strong, LEVEL foundation, we’re ready to start building the wall up. The foundation took us about three hours. Mariano assures me that the slow and meticulous pace was essential to ensure the base was strong. The pace will be much quicker now for the remaining layers. Stone by stone we place the layers, with a small dollop of Liquid Nails (exterior/landscape version) between each.
We use a string to be sure the front of the stones are aligned, and I check every one with a level just to be safe. Just as Mariano promised, every one is level, because we started with an awesome foundation.
Lastly, Mariano cuts the corner pieces to fit, and we finish the wall with cap stones. In total, it took about six hours to build this wall.
Step 7: Fill the Bed. We’re using a combination of soil builder, soil conditioner, lobster compost and cow manure to fill our bed — a total of 48 bags to fill 66 cubic feet. You can work with your local nursery to find the right combination and quantity for your bed. I have two good helpers for this step — my son and husband — which is invaluable since there is almost 2,000 pounds of soil to be hauled, lifted, dumped & churned! Also, because our bed is against a fence, I’ve lined the fence with landscape cloth so the soil won’t wash away through the slats. I also use the cloth to cover the drain pipe running through the bed.
Ready to help, straight from baseball practice.
The total time we invested in this bed — between prep, building and filling — was about 12 hours. The cost for stones and soil was about $600. The stone costs vary depending on the kind of stone you choose, and wood would be considerably less expensive. Also, the soil was a significant contributor to the cost — I chose top of the line soil and compost, but there are less expensive options that are just fine. Also, a smaller bed would require less soil, so keep that in mind when budgeting.
And we’re done! Here’s the finished product, ready to be planted, which will come next weekend, after a much-needed rest.