Last summer, I built a couple of corrugated metal raised garden beds for the side of our house. The planters were a huge success and produced carrots, kale, and spinach through the summer and into the fall. I built them fairly late in the spring, so I didn’t have to worry too much about covering the plants.
This is despite us being located in the high desert where the risk of frosts, or even snow, persists well into June.
We hope to start planting in mid-March this year, so building raised bed covers is necessary.
Why Add a Raised Bed Cover?
Adding a cover to a raised bed can help increase the interior temperature during the day and blunt the extreme colds during the night. This can mean the difference between a thriving garden or dead plants during frigid winter nights or surprise spring frosts.
The added heat during the day can also be stored through the night with water towers or milk jugs filled with water. They will warm during the day and slowly release the heat at night.
While I tend to plant a lot of frost-tolerant plants that have shown to be pretty hardy, even in sub 20-degree temperatures, they don’t exactly thrive when left uncovered. Adding these raised bed covers should help them get a head start before the heat of summer arrives.
Types of Raised Bed Covers
I considered many different options for building raised bed covers for these planter boxes. The boxes are approximately 48 inches square and stand 25″ tall.
I wanted garden bed covers that could easily be opened and didn’t restrict reaching any part of the box for planting, harvesting, etc.
I also had some greenhouse-grade plastic on hand, so I wanted to incorporate it rather than using plexiglass or corrugated plastic panels.
A few of the raised bed cover options I considered were:
- Hoop Cover
- A-Frame Cover w/side lid
- Square Cover w/top lid
- Angled Cover w/top lid
Hoop covers are the cheapest and easiest option for adding covers to raised beds. These covers are made with flexible PVC pipe, rebar or pipe strap, and plastic covering.
I like them for their simplicity and cheap cost, but honestly am not a fan of having to roll the plastic over the hoops and secure the sides and ends every time I want to access the planters.
These would be my go-to if we had in-ground garden beds, but I decided there were better options for raised beds.
As the threat of snow here is very real well into late spring, I wanted to consider options to shed snow. The A-Frame style raised bed cover checks that box. The idea behind this style of cover is that one or both sides of the A-frame lift open so you can easily access the garden bed.
Building the bed out of clear corrugated plastic would have been my choice as they are pretty easy to build.
Square Garden Bed Cover
Building a square garden bed cover is probably the most straightforward option, but, as discussed earlier, it will collect snow and risk collapse if not cleared quickly.
Angled Bed Cover
This was the choice I ultimately chose. The framing is similar to the square cover, but one side is higher than the other, so snow should slide off. The entire top of the lid lifts, and the sides aren’t so high that you can’t reach into the bed from almost any angle.
Building a Raised Bed Cover
To build the raised bed cover, I chose to go with some old maple I had picked up on craigslist a few years ago. You could just as easily go with 2×2 boards from a store like Lowe’s or Home Depot.
Those stores will even cut the lumber for you, so all you’d need to do is assemble the pieces once you get back to the garden!
Note that I built this cover to fit my planter boxes, but the dimensions can be very easily modified to fit any square or rectangular bed. For longer or shorter beds, you may need more or fewer braces to help hold everything together.
Tools Needed for this Project
There are only a couple of tools needed to make these garden bed covers so this is a great project for a beginner woodworker or homeowner who only has access to a few tools.
- Miter Saw (optional)
- Pocket Hole Jig
- Power Drill
- Heavy Duty Stapler
Building the Frame Base
I cut the base to fit in the middle of the top of the planter box. The long pieces were approximately 44 inches long, and the short pieces were around 41 inches.
I then joined them together using pocket hole screws. I like the simplicity of pocket hole screws for simple outdoor projects like this. They make for quick joinery, work well in various woods, and make it easy to break down the covers once they are no longer needed for the year.
Adding the Front and Back Framing
Once the base is screwed together, you can add the front and back framing. The back frame was cut to 18 inches high, while the front was cut to 8 inches. This leaves a 10-inch drop over the length of the raised bed cover, which should help shed snow and makes the garden bed easier to access.
I cut three pieces of wood at 16 inches long, and pocket hole screwed them into the base. I then cut another piece at 44 inches and attached it to the top of the frame.
That was repeated for the other side of the frame, with the pieces cut to 6-inch lengths.
Note that these shorter lengths can make driving in the pocket hole screws challenging. I made sure to orient the pocket holes facing out for easy access. The middle support piece was pocket holed in the bottom before the top was added and then screwed through the top to attach it fully.
Attaching the Sides
Cutting the side pieces was simple as I clamped a longer board to the frame and marked cut lines on both ends. This meant I didn’t need to measure the length or cut angles!
After cutting both pieces out on the miter saw, I pocket hole screwed them to the frame. Adding a couple of clamps to the frame to rest the side pieces on while screwing them in makes life a whole lot easier.
Adding the Top
The top was straightforward as it was just another square similar to the base. Note that this square needs to be slightly larger than the base as the angled profile makes it somewhat longer.
I measured out all the pieces and pocket-holed them together. From there, it is on to sheathing the raised bed cover.
Finishing up the Rased Bed Cover
I used plastic sheeting designed for greenhouses to sheath the garden bed cover. The sheeting is UV resistant and should hold up for 3 to 4 years of exposure to the sun.
Garden supply stores will often have rolls of this plastic available that can be cut to size. I purchased a sheet approximately 12′ x 12′ in size, which should be enough to sheath this garden bed and another larger bed next to the house.
This part wasn’t pretty, but I rough cut the plastic to size and stapled it to the frame using a heavy-duty stapler. Having a pneumatic stapler would have been nice as I was using hard maple, which is a bit too hard to fully drive in staples with a handheld stapler. In the end, it did the trick, though!
To attach the top to the rest of the frame, I just draped the plastic over the back of the top and stapled it to the top of the frame. I keep a spare piece of wood next to the frame that can prop it open if the interior gets too hot or I need to work in the garden.
Final Thoughts on the Raised Bed Covers
Overall this was a straightforward project that only took a couple of hours to complete. I’m excited to get a head start on planting this year, and this bed should be full of leafy greens here in a few weeks.
Derek grew up woodworking in his father’s shop and has since gone on to start up a successful woodworking business on Etsy. In his spare time, you can find him mountain biking, skiing, or writing.