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The home page in this series on building raised bed gardens is Raised Beds Jim’s Way.
At each corner of the bed, and at 4′ intervals down the sides of the bed, we will put two vertical PVC pipes. These have multiple purposes, but the biggest one is for trellises, animal protection, and/or tunnel structuring.
Trellises are used for hanging crops like cucumbers and small melons. Animal protection is fencing material to keep animals out of the garden. It doesn’t help against underground pests, though. It only works on things like rabbits and deer.
Tunnel structuring is semi-circular polyethylene pipe. This pipe comes in rolls up to 100′ or more. I cut it in 7′ or 8′ lengths, and use the curved nature of it to make ribs across the garden beds. Then, put sheets of plastic over it and weigh them down with heavy objects, and a nice tunnel is created.
This kind of tunnel can add a month to each end of the growing season. Since I live in Minnesota, this is pretty important. We once harvested a bushel basket full of produce on Thanksgiving Day. The first frost was in September that year, and the first freezes started in October. Yet, the garden still grew. The tunnel was the reason.
Two Kinds of Pipe Segment Pairs
I use a pair of 1-1/2″ pipe segments at each corner. I also use two pipe segments at each 4′ interval down the long side of the bed. The segment pair at the corners has one pipe segment on each board, so an imaginary line drawn between them cuts across the boards diagonally. On the sides, they are place side-by-side, touching each other.
In both cases, plumber’s strapping is used to hold them on. Plumber’s strapping comes with convenient holes in it. The screws hold the pipes in place.
On the corners, two straps are used for each pipe segment, wrapping around to the other board. On the sides, two straps are used to hold both pipes. With both pairs, the strapping is attached 2-3″ from the top and bottom of the planks.
The segments themselves are cut to be approximately 6″ longer than the width of the planks. In my example, the planks are 12″ wide, so the pipes are 17″ long. Why 17″ and not 18″? Because the pipe comes in 10′ lengths, and 18″ leaves a foot of pipe unused and useless. Cutting them to 17″ allows us to get 7 segments out of one 10′ length of pipe, with no waste. The six-inch figure is an approximation.
Of course, if your planks are of different width than the 12″ planks I used, you will have to adjust these numbers. But, make them approximately 6″ longer than the plank is wide.
For the corner segments, each pipe segment is held down with two pieces of plumber’s strapping. The pipe mounted flush and held on by a piece of strapping with the end holes about 10″ apart. I’ll call these “11-inch straps” herein, but they are not necessarily exactly 11″ long. If you get the kind of strapping that has holes every half-inch or every inch, this might make measuring easier.
Plumber’s strap can have small or large holes in them. Cut the pieces such that there’s a half-inch to inch of extra strapping on the ends.
Attach all four pieces of strapping to the boards 1-1/2″ from the end of the planks. Attach the four pieces of strapping to the corner with one screw each. In our example, the end board overlaps the side plank, so put the screw in the long plank 1-1/2″ from where the boards meet, not from the outside of the bed. If we put the screw to close to the end of the board, it can split the wood.
Because there are two segments of strapping on each pipe, and there are two pipes, these will have to be offset from each other in order to prevent having to screw through the other pipe’s strapping. I set them in place at the same time and touching each other, just so I don’t accidentally overlap them later.
Once all four pieces of strapping are in place for a corner (with one screw each), you can mount the pipe segment. The extra 6″ of pipe will be in a hole in the ground, but for now, they can stick up above the tops of the planks.
To place the screw into the strapping after wrapping it around the pipe segment, start by pulling the strapping snug and touching the end to the plank it’s not already attached to. Then, put the screw through the last hole, but at a 45-degree angle to the board. With your fingers, press the end of the screw slightly into the board to mark the spot. Then, tilt the screw so it’s perpendicular to the board. This will loosen up the strapping by a quarter-inch or so, which will allow the screw to be driven in all the way to the surface of the plank1.
Repeat for the other three screws, and repeat the corner instructions again for the other three corners. If you’ve done it right, you’ll have a rectangular plank bed with pairs of pipes sticking up at each corner.
The side segments are different. Here they go side-by-side, with two pieces of strapping holding them in place. One goes near the top and the other near the bottom. 11″ segments of strapping work well for this. At each 4′ interval down the long side of the bed, we’ll put two pipes in place.
At the place where you want to put the pair of segments, draw a vertical line down the side of the plank. This will be the place where the two pipe segments meet. From that line, measure 3-3/4″ to the right2, and about 2-3″ from the top of the board. Make an X-mark at this point. This is where the screw goes. Make another X-mark the same distance from your line, but towards the bottom of the plank. The exact distance isn’t important, but it should be at least 2″ from the one on top and 2″ from the bottom of the plank, to prevent the wood from splitting.
Screw through the last hole on one end of an 11″ segment of strapping, at one of the X-marks you just made. Because the segments are 11″, they will extend past where 3-3/4″ would be on the other side; don’t worry about that. The extra is to go around the pipes. Screw the other piece of strapping to the other X-mark.
Put both pipe segments in place under one of the pieces of strapping. Using the same 45-degree angle trick mentioned above for the corner segments, attach the other end of the strapping.
Repeat for the other piece of strapping on this pair of pipes. Then, repeat all these steps on all other locations on the long side of the bed.
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- If we had tried to drive the screw at the end of where the strapping could reach, it would have pulled the strapping too tightly around the pipe, making moving them later difficult. It also could have damaged the strapping. The 45 degree angle trick buys back a small amount, allowing more flexibility.
- You can do it on the left if desired. I’ll use the right side in my example here.