A raised garden bed can easily be converted into a mini greenhouse using inexpensive, common items, allowing you to grow veggies, flowers, and plants all year.
This type of structure can also easily be removed if you live in non-stable climate areas where the weather changes are harsh and frequent. The design is also beneficial because it allows you to remove the cover whenever you need to weed the garden or want to plant new seeds. Depending on what your intentions are, some days you may need to remove the tarp entirely, while other days you may only need to remove the end pieces.
Even though this mini greenhouse design may appear small, you can still install a standard irrigation system for easy watering, or you can take advantage of the removable tarp to access the plants with a garden hose.
Step 1 - Build a Raised Garden Bed
For those of you who have already built a raised garden bed and want to convert it into a mini greenhouse, you can move directly on to step two. All others should first build a raised garden bed before following these instructions for converting it. Once you’ve built a raised garden bed, you can begin planning the conversion.
Step 2 - Take Measurements
Measure the length and width of your raised garden bed. This will determine the size of the tarp you’ll need to purchase in order to create an effective enclosure for growing. These measurements will also determine how many arches you will need to create from the electrical PVC.
Step 3 - Purchase Materials
Once you’ve taken measurements and determined how much material you will need, you can visit your local garden supply store or local home improvement store to get everything you’ll need for the project.
Step 4 - Place Arches
When building your mini greenhouse, it is important that you place pipe arches made from your electrical conduit PVC at each end of the structure. The arches shown in the picture are 40 inches tall from the top of the wood bed to the peak of the arch. You can adjust the width of the arch by bending the pipe to fit the width of your bed. You can adjust the height of your arch by lowering or raising the arch further down or higher up the sides of the garden bed before fastening them in. Be sure that you are consistent with the height of the arches.
Place additional arches approximately every 4 to 6 feet in between the two end arches, fastening each arch to the wood with the electrical clamps and wood screws. You will want to use two clamps on each side of the arch when fastening the arches to the wood, one higher on the arch than the other.
Step 5 - Complete the Pipe Frame
On top of the arches, run the electrical PVC piping the length of the garden bed and secure it by fastening it to the top of the all arches with electrical PVC clamps screwed into the top of each pipe arch.
Step 6 - Attach Velcro to Arches
In order to properly secure the removable tarp for an effective mini greenhouse, you’ll need to use Velcro strips on both the end arches and the tarp. Attach the stiff (hook) side of the Velcro to the top of each end arch. Take your time to ensure that the Velcro properly adheres to the arch. You can add as many Velcro strips as you’d like to ensure full security once the tarp is on.
Step 7 - Size the Tarp
Cut the tarp to be the length of the bed from the arch at one end to the arch at the other end. Cut the width of the tarp to cover the wood on both sides of the garden bed. Make sure to keep the tarp long enough that it overlaps with the wood sides, trapping the heat inside the garden and creating the greenhouse effect.
Step 8 - Attach Velcro to Tarp
Attach the soft (loop) part of the Velcro to the bottom side of each end piece along the arch. Take your time to ensure that the Velcro adheres properly. The bottom side of the tarp end pieces will attach to the Velcro on top of the main tarp.
Step 9 - Cut End Pieces
Use leftover pieces of the tarp to cut a piece in the same size and shape of the arches on both ends of the garden bed. These pieces will need to be about 2 inches wider and longer than the arch itself in order to fasten them with Velcro.
Step 10 - Attach Velcro to End Pieces
Attach the soft (loop) part of the Velcro to the bottom side of each end piece along the arch. Take your time to ensure that the Velcro adheres properly. The tarp end pieces will attach to the Velcro on top of the tarp running the length of the garden.
Step 11 - Attach the Tarp
Lay the tarp across the arches, attaching the Velcro that is on the bottom of the tarp to the Velcro that is across the top of the arch end pieces. Attach the Velcro that is on the top of the tarp to the Velcro that is on the bottom of the tarp end pieces. This allows for the end pieces to be removed for easy access to your garden while keeping the main tarp in place.
Step 12 - Place the Tarp Clips
Once the tarp is attached to the greenhouse, you will attach the tarp clips every 2 to 3 feet as necessary. Each end piece will require at least two clips to properly lock the heat in.
Step 13 - Screw the Fasteners
Now you will pull the tarp clips snug and screw them into the wood. These tarp clips allow the tarp to easily be removed once the weather permits.