Rock Solid Raised Bed

Richard Tullis

Richard Tullis › Richard Tullis is an artist/photographer living with his wife Karen in Portland, Oregon. An amateur ...

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Karen and I are passionate about growing organic produce in our lawn-less yard.

For our first growing season, we weren’t prepared to commit to a permanent garden layout–we knew we had a lot to learn, including where the sun fell (or didn’t), so our first try at raised-bed gardening was intentionally temporary: we cut the bottoms off of large black plastic nursery pots, partially buried them in the ground, and filled them with a mix of compost and soil. This approach works great and we still use it to grow a forest of tomato plants every summer.

However, for four-season gardening and crops that need a boost in soil temperature, we decided a more permanent raised bed solution should be built.

I’d been searching for an interesting, visually aesthetic option. On a sunny spring Saturday we drove over to Farmington Gardens (a favorite local nursery) to look at their modular concrete block raised beds. Karen loved the idea: a wall high enough to sit on while tending our plants and weeding. And concrete as the material of choice was appealing because unlike wood-walled beds, I wouldn’t need to replace the concrete blocks after a few rainy seasons. Wood rots pretty fast here in the wet NW, as is evident after each big winter storm when we see toppled wood fences in our aging neighborhood.

We stopped briefly at home to collect a discount coupon before heading over the Willamette River to our local Basalite outlet to see what they had available. We decided on 15,000 pounds of Century Stone engineered concrete blocks, to be delivered that coming Thursday. Cedar Mill Lumber’s truck delivered 8 cubic yards of quarter-minus gravel. This gravel provided a level foundation, drainage, and fill for the blocks.

Building engineered concrete block walls turns out to be pretty simple. First, it’s important to measure out your garden bed before digging. I used four stakes to define the inside edges of the bed and a leveled string stretched tight between the stakes to guide me. It took me a few days behind a garden shovel to dig trenches deep enough for a stable wall.

The trench needs to bury the first course of blocks for a short wall and more blocks if the wall’s higher. Our site is on a slight grade so I had more digging on the east side to make the wall even and level. The directions state that gravel eight inches deep and four inches wider than the blocks is required. I made a miscalculation and had to excavate an additional few inches around the whole trench. I mush have forgotten the measure twice dig once rule… Next, tamping to assure a level foundation, a level gravel bed makes laying the first course of blocks go quickly.

Karen, our neighbor Brian, and his son Charlie helped build the walls one extremely rainy weekend. They brought blocks faster than I could place and level them, then fill them with quarter minus. At the end of the second day the garden bed was ready for compost.

Fast-forward to the end of our first raised bed harvest. The concrete blocks helped warm our soil and made our Nightshades extra productive during our short growing season. Last winter we harvested root vegetables. I’m glad the lawn is gone.

What’s your favorite thing to grow in your raised garden bed?

Photo Credit: Richard Tullis