How To Build A Self Watering Raised Garden Bed – Note from Kirsten: Today’s post was brought to you by Ken Charm. Ken works at the sales counter at our Everett location and recently became involved with Dunn through the Northwest Flower & Garden Festival.
Ken studied environmental science at Western Washington University and worked as an environmental consultant for 14 years, so he knows a thing or two about working with different types of wood in the garden. Today, Ken shares how to build a self-watering raising bed (also referred to as a planter bed, planter box, garden bed, etc.). Take it, Ken!
How To Build A Self Watering Raised Garden Bed
I’m excited to show you how Kirsten and Icreed made a durable bed that would be a great addition to any garden. Took it to water my vegetables. I also want “insurance” so that I can go away for a long weekend and not worry about my vegetables dying (or asking the neighbors to water the plants).
Raised Garden Beds
A self-watering bed consists of two parts: the tank and the soil. The tank holds the water and the soil removes it and stays wet. The physics involved here isn’t too complicated, but the important thing to remember is that water can only penetrate so far – 12″ to 18″ at most. I’ve been growing the borders with 28 inch planters, but want to make sure my herbivorous pug doesn’t get into it. Let’s start.
Make sure the area you choose for your bed has enough light for your planting. In my case, I plan on growing vegetables, so full sun is critical.
You can level the area now or (like me) level the area after the frame is done.
I decided to make a 4′ x 8′ frame. The scale of these measurements fit my yard nicely and coincided with heavily discounted materials I found (it helps to know the people at your local wood shop). I use these measurements for this, but you can change them as needed to fit your space.
Diy Self Watering Planter
To begin, you will need to cut some of your wood into shorter lengths. (Remember, any cut you make in pressure treated wood must be treated with end cut solution.) Cut two 26″ long pieces of 10′ by four by four and cut two by sixes in half so that you have two pieces 48″ long. Also cut one of the two of you in half with eight. You’ll use one of these 48″ pieces on each end of the planter. 26″ two-by-fours (this should make a rectangle when you’re done and when you’re standing up, you’ll add a 48″ piece of two-by-eight between the two corner posts. Six boards for support Once you’ve finished one end, repeat on the other end.
Quick note: My beds are 28″ long because I found copper colored metal roofs that are 26″ long at a discount at my local lumberyard. (Note: Dunn Lumber has plain galvanized metal roofing, and colored roofing usually requires a separate order.) I needed a raised bed to keep one of my pugs out of the vegetable garden—she loves to eat anything edible,
Fresh lettuce – and at that height, he can’t jump at all. Make your bed as long or short as needed, as long as it is within 12″ to 18″ of what the bottle bed can do.
After finishing the two short ends, attach the long (8′) two-by-sixes and two-by-eights to the four-by-four posts, making a rectangular frame with four-by-fours inside. By having the four-by-four inside the frame, we can avoid putting screws into the end grain of the wood, which is much less capable of holding a screw than the side of a four-by-four. I used two to three screws on two by sixes and three to four screws on two by eights.
Diy Self Watering Raised Planter Bed
After building the frame, level the site. My yard has all kinds of humps and dips, so just leveling under the frame and all 32 square feet is a lot of work. Some people call it laziness—I call it efficiency!
My raised bed is on the fence. If yours is free, skip to step 6.
Now that we have the bed frame and site level, it’s time to add the trim. This is where it all starts to come together. Using a grinder with a cut-off wheel or a circular saw with an old carbide blade turned back, cut the metal roof to length.
For the side facing the fence, I used parts of the cover sheets that the manufacturer uses to protect the roof during shipping. It’s the same profile with the same guardrails, minus the nice color, but who cares about the color on the panel facing the fence? After cutting, pull the frame away from the fence and attach the liner. At this stage, I will only add trim to the side adjacent to the fence. The rest of the trim will be added in step 8. For the hardware, I chose to use a plain galvanized screw instead of a colored screw. Galvanized screws are readily available and I like the contrasting color, but the choice is yours. When you’re done, move the bed back to the fence.
Building A Self Watering Raised Garden Bed
Place the pondliner in an empty box, smoothing the liner on all sides to minimize wrinkles and folds. There are creases in every corner, but we don’t want too many. Don’t skip this step – the liner creates a sealed environment inside the planter box, which is essential if you want the bed to self-water.
Sew the lining to the top of the frame. I used my spirit pistol. You can also use an electric gun, but there are so many staples involved that when you can use a manual staple gun, it’s worth renting or buying one that gives you some mechanical help. I bet I used at least 500 staples and I don’t want to do that with my handgun!
Using a utility knife with a fresh blade inside (remember: a sharp knife is a safe knife), cut off the excess lining.
Now it’s time to add the rest of the lining. Use a tape measure and find the center of the 8-inch metal roof. Mark the center with a dot and join each leg in a nice straight line, working outward from the center along the “valley” in the ceiling (where the screws go into the box frame and hold the ceiling in contact with the box). When you’re done, you’ll have three rows of identical dots on both sides of the 8′ and rows of identical dots on the remaining 4′ side.
S333618wb Self Watering Mobile Elevated Planter In Blue
For this step, it helps to have an extra set of hands—at least while you’re placing the first few screws. Align the top of the ceiling level with the top of the frame. The screws are self-adhesive, so you don’t need to pre-drill. Put a screw through one of the dots at one end while one friend holds the other. And don’t forget to wear gloves! Cuts are one
Descending from a metal roof is unpleasant (don’t ask me how I know). Repeat this process on each side.
The edges of the cut metal roof are sharp—we use fence board to cover them. Using the planter box as a measuring tool, mark the height of the planter on a piece of fence board, then cut the board to length. Attach this board with screws through the ridge section of the metal trim. You can use one-by-six fence boards, but I prefer the narrower line of a one-by-four board. These are not structured so go by your eye. You can also order metal flashing to match or finish a metal ceiling to do the same thing: hide sharp edges.
To complete the frame, we add wood to the top. To do this, place a two by six ten foot level on the planter flush with the end of the box. I chose to use pressure treated wood here because a customer told me the copper keeps snails and slugs from getting into the bed. I don’t know if it still works, but I thought I’d give it a try. To hang over two-by-six end fence board – measure for a miter cut that’s wide on the edge. If it helps, use a piece of fence board for spacing. Then cut. If you are using pressure treated wood, remember to apply a grain sealer (the wood preservative mentioned in step 2).
Pcs Large Elevated Flower Planter Box
Remember to insert over the cut – it’s easier to cut off a little more wood than it is to add it back. Someday, I will invent a plank stretcher and become rich