Budget Cedar Raised Beds
Introduction
March 3, 2010
When we moved into the new house one of the major priorities we had was to reestablish the strawberry patch. The original patch Anna created back in Madison was phenomenal. She routinely got quarts per day out of it during the peak season.
With the heavy clay soil around the new neighborhood I was doubtful it would be possible to match what we had at the old house, even with the expanded gardening space. We quickly realized that a raised bed would be a good option. Anna's initial attempt to dig up a strip for raspberries was complete agony, like trying to shovel through tar. So we decided to put in some raised beds to host the strawberries.
We had several raised bed in the garden at the old house which we had been using for several years. When I built them I really was'nt too worried about how long they would last. They were built out of "brown" treated lumber and only held together with standard drywall screws.
When I built the original beds I had my reservations about using treated lumber, considering the treatment is chemically the same as rat poison. According to several studies it was safe to use it for gardening. One blunder I didn't realize I was making at the time was that the standard drywall screws don't held up very well outside. The beds held together for about three years before I had to start performing yearly maintenance to keep them together.
This time around we decided to splurge and try to build something that would last. Anna and I are both big fans of natural building materials so cedar seemed like a good choice. Plus we were planning on building a cedar fence to keep the toddlers from terrorizing the neighborhood so we thought it would match.
Raised Bed Materials and Planning
Once we decided to go with cedar we started pricing out options. We were looking to have about 1' of flower bed above ground. We also wanted solid corners so the beds would last. Finally an easy to build design that was not an eye sore was also preferable.
If you add up all the parts the cost was around $110 per bed.
Cedar Board Stock
The cheapest cedar board available seemed to be the standard cedar deck planking. Its about 6" wide by 8' long. The cheapest source we found for the boards was Menards at $6 a piece. We our design we would need nine boards per bed.
For the corners we ended up going with 4" x 4" x 8' cedar beam. One 8' board would be enough for each bed when cut into four 2' sections. These were a bit pricey at $22 each but only one would be needed per bed.
On the longer 8' side-walls I thought some mid wall supports would be prudent to hold back the weight of the dirt. For this I opted for a 2" x 4" x 8' rather than a full 4" x 4" to save some money. These were about $10 each and one board would be enough for all four side wall supports required for each bed.
Exterior Screws
To hold it all together I picked up some exterior deck screws to hold the side walls together. To brace the corners I bought some 4" exterior screws and some galvanized right angle brackets. A cheaper option to the right angle brackets (they were about $0.75 each) would be to buy extra 4" screws.
To keep the water out of the top of the cedar beams I picked up a tube of black jack roofing sealant. I thought the black color would look better than the white, gray, or clear colored caulks.
Bed Corner Supports
We have very heavy clay soil around our house. From reading random articles on the web and a few home improvement books it sounded like it would be a good idea to keep the buried bottoms of the cedar post from sitting in water. On easy solution to accomplish this was to dig down a little extra in each post hole so I could fill the bottom with some rocks. A bag of rocks was actually rather cheap at $5 bucks (I think). I used about three bags per bed. Alternatively if you have some rocks laying around the yard they will work fine.
To keep the post from sliding around I also dumped about a 1/4 bag of quick create in each corner hole for each bed. One bag is around $3. Its heavy and somewhat messy however so you may want to bring a friend with a truck to the hardware store with you.
Alternate Materials
One alternative to using cedar would be to use treated pine lumber (like I did for the beds at the Madison house). Considering its treated with rat poison to preserve it against rot a lot of people are hesitant to use it to grow their vegetables in. Like I said I thought I read a study somewhere where the treatment chemicals would not leach out. However this time around we thought the few extra bucks for cedar was worth it. It just looks a lot better than treated lumber.
Raised Bed Construction
Side Walls
For the side walls of the raised bed I used three of the cedar boards in two layers. The two outer boards were attached the inner board spaced apart by1 1/2". To build a couple of quick and easy spacers I shaved off two 3/8" end pieces of a 2" x 4" scrap. It was easy enough to construct the three side walls. I started by placing two cedar decking boards on the floor seperated by two of the homemade 2"x4"spacers. Then I centered the third board over the other two on the floor and screwed them together. Once the boards were screwed together I removed the spacer. The gap in the center of the two boards gave the side walls I nice three-dimensional look.This gave me one 8' side wall for the bed. For one bed I needed two 8' walls and two 4' walls. To get the second 8' wall I just repeated the process for the first one. To make the two 4' walls I made a third 8' wall and then cut it in half to get the two 4' sections. Corner Post and Mid Wall Supports
For the corners I cut the 4" x 4" x 8' cedar beam into four 2' sections to serve as the corner post. I used extra long 4" exterior screws installed at an angle from the side wall into the post to hold the corners together. I kept the top of the post about an inch above the side walls because I thought it looked nicer.As additional support for the corners I added some galvanized right angle brackets (two per each wall/corner post intersection for a total of 16 for one bed). All those right angle brackets may not have been necessary but I like being thorough. A cheaper option to the brackets (they were $0.75 each) would be just screw in some extra 4" screws from the exterior side of the corner post into the side-wall ends. The assembled bed will be heavy but I was able to move it around easy enough. Two people should definitely be able to manage it. I would recommend placing the bed where you think you will like it then taking a few steps back to take a look. Once you dig the bed in its not going anywhere.Installation in the Ground
With the four corner post and four mid wall supports I needed to dig eight holes per bed. This was honestly the hardest part of the job due to the heavy clay soil and many tree roots in the backyard. To mark where the holes would go I picked up the bed, got it in position, and then dug around the post. Any easy way to make sure the bed is square is to use a tap measure to measure the diagonals and adjust the bed until they are equal (just like the ancient Egyptian pyramid builders). Then I put the bed aside and began digging out the holes.In addition to digging the holes I also dug a shallow trench for the side-walls so the dirt inside the flower bed would not erode out the bottom of the bed under the side walls. While digging the side wall trench I saved some of the grass sod to place back along side the outside of the bed after it was was in its final position. Once the wholes were basically dug all the way down I picked up the pre-assembled bed and dropped it in the holes. It took a few iterations of placing the bed in the holes and taking it back out to get the bed level. When I put my beds in I probably should have spent more time on this step but I was in a hurry to get them done. Even if they are not perfectly level the beds still look pretty good. Fill
We ended up building three 8' x 4' beds. Rather than buying dirt by the bag we called a local landscaping company and ordered it by the yards (three to be exact). I think it was something like $30 per yard delivered to our driveway (need to check on that figure). We had them dump it in the drive way because that was the closest we could get it to the backyard without having a heavy truck drive across our neighbor's yard. A wheel barrow came in handy here (we borrowed our neighbor's).
I would plan on ordering a little extra dirt or plan on buying some extra single bags latter to fill in any areas that settle down.
Tar Top for Post
I also sprung for a tube of blackjack to seal the top of the post (corner and mid-post). I thought the sealant would keep the moisture out of the post and still look relatively decent. At the hardware store I also saw some copper beam tops that would work but I thought they were a bit pricey for flower beds.
Performance of Raised Beds
So far the new strawberries, asparagus, and flowers seem to really like the new flower beds. The true test will be this spring to see how well the plants come back and what sort of second year harvest Anna gets on the strawberries. More to come...
Follow Up Projects
Anti-Rabbit CoverAnna noticed that rabbits were getting into one of her strawberry beds and requested a solution. What I came up with was a light, cedar framed cover. I used cedar 2x4 to form a center post and then attached the cover with hinges so it would be easy to flip up to harvest the strawberry crop.
The wood color of the new cedar top does not currently match the old cedar beds put in a year ago but I am planning on with another year of aging the two pieces will match.
Cedar Sand Box
Woody and Teddy really enjoyed playing in the plastic sand table we inherited from friends. The one problem with it was that the sand didn't stay in the table very long. A lot of it ended up on the patio right next to the back door which made it easy to track into the house.
Since the beds went together well and they looked relatively decent we decided to make a sand box in the same style and locate it in the back corner of the yard. The idea on the location was that any spill overs would just fall onto the grass. Also the kids would have 60 feet of walking where the sand could fall off before they could get into the house after taking a bath in the sandbox. To make it big enough I increased the 4' ends to 6' in length. I also built in a ring around the inside of the bed as a bench to sit on. To support the bench I used cheaper treated lumber rather than cedar since you would not be able to see the supporting wood.To keep the leaves out of the sandbox in the fall I built some cedar covers for the sandbox. The main construction material for the covers was cedar siding framed by cedar 1" x 4". The initial design was a bit flimsy so I had to reinforce it.The picture to the right was taken during a mid winter thaw. The ground was still frozen so there was a lot of standing water in the beds from the melted snow.Cedar Air Conditioner Buffer
This is a future project for next summer. Right now the buffer between the patio and the air conditioner is a bush which Anna hates. My plan is to ripe up the bush (or wait till Anna takes the initiative) and then replace it with a 4' foot cedar wall in the same style as the flower beds and sandbox.
