Up until this week, my ventures in hardscape have been limited to two dimensions. Well, perhaps one dimension: flat. I've done brick edgers and flagstone paths, but nothing that possessed the characteristic of altitude. So when my wife asked me last week what I wanted for my birthday, I naturally said, "a retaining wall." My birthday happened to coincide with a some vacation from work, so this past weekend, I started planning a raised garden planter that is part patio bench, part block retaining wall.
Before the project, this site was one of our landscape problem children. We were never able to decide which plants would fit the site. Years ago, when friends gave our son a 'North Star' cherry tree, we placed it at a focal point on the corner of the patio, but never developed the surrounding bed. This is what the site looked like a few days ago:
The first step in the project involved repairing the top boards of the patio bench that had started to rot and crumble from years of exposure. The base of the benches was solid, so ripping off and replacing the top boards with treated "thick deck" planks (cost $23.86) brought the benches up to snuff. I attached two eight foot treated 2x10s ($12.87) to the 4x4 posts of the bench to form the back of the raised planter. Coated decking screws (2.5") were used throughout.
To prevent direct contact between soil and wood, I attached black plastic (3 mil) to the yard side of the 2x10s and posts.
Once the benches were completed, I started the trench for the retaining wall. This involved relocating some existing plants (including two clumps of phlox and a few daylilies) and simply removing some others (including Rudbeckia and Echinacea).
I dug the trench about 6-8 deep around the perimeter of the patio, about 28 inches from the patio boards. To avoid the cherry tree, I decided to cut the angle of the patio corner at about 45 degrees. (As you can see, my son was a big help in digging the trench.)
To prevent damage to the lawn, we piled the soil from the trench against the plastic lining. Later, I'd use it to backfill the bottom two courses of the retaining wall.
I filled the bottom of the trench with 3-4 inches of multipurpose gravel ($26.72 for eight 0.4 cu. ft. bags) to serve as a leveling base. A quick measurement showed the based of the trench to range from 19-23" from the intended top of the planter. Obviously, some leveling and an extra course of block along the western side of the patio would be necessary.
After the gravel was laid, we called an end to Day 1 of the project.
Since our truck only has a half-ton payload, I knew transporting the retaining wall block would involve several trips to Menards (one of our local home improvement stores). On the first trip, I purchased 50 Crestone II Autumn Blend 17 lb. retaining wall blocks ($77.04) and began the most challenging part of the project -- getting the first course of block level. Using a level, tamper and rubber mallet, I slowly made my way around the approximately 24' base of the retaining wall. Each block had to be placed, leveled left/right and front/back on the gravel base as well as with its adjacent neighbor. As each block was leveled, I placed a second course block on top to prevent it from shifting too much as the next block was leveled. I used soil from the trench to backfill against the first course to hold it in place.
To account for the slope of the yard and to ensure the bottom course was below soil level, an extra course of block was used on the western side of the retaining wall.
Once the first and second course were down, the project attained the feel of a giant Lego project. The Crestone block have two small nubs on the top, which line up with a slot on the underside of the covering course. This ensures alignment as well as prevents the blocks from sliding off one another by locking one course to another.
A second trip to get 58 more wall blocks ($89.37) and more hauling of the 17 lb Legos completed most of the wall, with the exception of the capstones.
Another trip across town to Menards started Day 3, where I loaded 28 capstone blocks to finish the wall. Certainly the easiest part of the project, the blocks went straight from the pickup bed to complete the retaining wall.
Later in the day, I made my first trip to the Urbana Lanscape Recycle Center to pick up a load of compost ($10). We've been using the LRC for mulch and compost for years, and for the first time, one of the LRC employees warned me of the weight of a cubic yard of compost. It seems they've weighed them out at 1.2 tons -- and we've regularly put a cubic hard in the bed of our 1/2 ton pickup. I guess there's a reason we always try to pick it up after a dry weather spell.
It was a low, slow ride home, but the first compost load just about filled the new planter, but came up about 1/4 yard short.
I woke up this morning and the forecast called for rain most of the day, and the first wave was just 90 miles to the west. So I hopped back in the truck and headed to LRC for another yard of compost ($10). I quickly unloaded the truck and scooped the last shovelfuls as the rain started to steadily come down.
A break in the rain later this afternoon allowed for a trip to the garden center to find some late season deals on plants to complete the project. The selection at this time of year is always sparse, but found two Blue Rug Junipers (Juniperus horizontalis 'Wiltonii'), two Sedum ellacombianum, and six English Ivy (Hedera helix) plants (combined total $52.66). To these plants, I added two hardy mums from the yard.
After transplanting, I swept the soil from the capstone and called it a project well done. The total cost came to just over $350, and took about 25 hours of work to complete.
Now that the backyard hardscape now has some altitude, I'm seeing opportunities for future improvements that I never imagined before. The next step is to cut in a ground level bed in front of the garden planter that incorporates the cherry tree, to help soften the edge transition between the lawn and the patio. There are also several other places where the yard slopes down toward the west where short retaining walls would create an effective terracing effect and better define the lanscape space.