Welcome to part 2 of Little Farm in the Alberta Foothills’ raised bed garden box feature! You can find part 1 here. In this post we will discuss the logistics of building the raised bed garden boxes and give you the details and specifics of how you can follow our design and what you will need. This straightforward plan can be started and completed in just a couple of days, making it the perfect weekend project! Let’s get started!
In Canada our building supplies and materials can be very costly to purchase from a retailer. You will find that if you price out the total to build a raised bed garden following this design that costs will add up quickly. We viewed this expense as an investment and decided that it was a priority in our budget. We chose not to cut corners in order to “do it right” – making the boxes large enough to suit our needs, predator-proof, and resistant to weathering. The hope is to make these beds last for many seasons and keep repairs to a minimum, saving time and money in the long run. Though our design is simple, you will find that it isn’t the cheapest one out there. For a couple of less expensive ideas, check out this design to find out how you can build a bed using recycled pallets, or this design if you happen to have available an inexpensive source of cinder blocks.
Garden Box Design
We knew we needed the Fort Knox of raised beds to keep at bay the many wily predators in our part of the world. Bewhiskered bandits and feathered felons are very clever at finding ways to steal your hard-earned produce by digging, gnawing, ripping, flying, or squeezing their way past your garden defenses. Though it’s possible that our design could experience a security breech, we have tried our best to proactively protect our garden produce against punky predators.
The garden box dimensions were chosen to maximize growing space and to provide deep soil to encourage vegetable growth and quality. The design was chosen with the building material dimensions in mind – the boxes needed to be both cost effective (ie. reduce cutting and material wastage) and time effective (less time spent making specialized cuts to fit a specific design and dimensions). For example, the 16’ x 4’ design was chosen to accommodate the average 8’ cedar lumber length. The height of the boxes measures in at around 16.5” (after stacking three 2”x 6” cedar boards). This height is useful when it comes to attaching the cedar boards to the 4” x 4” cedar posts. By cutting an 8’ cedar post into three sections at 32” you have enough room to attach the 16.5” boards to the post and have enough room to sink the remaining 15.5” into the ground for additional stability (refer to the drawings).
Hoop Top Design
We designed hoop tops with hinges for easy removal to tend, water, and harvest the garden boxes. For a 16’ x 4’ box you will need to plan to build two tops to cover the bed. The hinged hoop tops can be easily opened and closed with the addition of eye bolts attached to the hoop top frame base and the garden box itself. Install these on the opposite side from the hinges. Simply add a length of light rope by tying each end to the eye bolts; this allows the hoop top to stay open but off the ground since it will be suspended via the rope.
The hoop tops protect the beds from predators and the elements and make it easier to cover the plants to protect them from weather such as frost or hail. We also made the hoop tops quite tall so that plants that require quite a bit of vertical space, such as potatoes and peas, would have room to stretch up. For some crops it made sense to have the hoops hinged along the long (16’) side of the box and for other crops we placed the hinges along the short (4’) ends.
Untreated lumber should always be used for garden structures in which you intend to grow food. Chemicals can leech into the soil and from there into your fruits and veggies. We used cedar lumber because it is naturally rot-resistant and untreated. Though cedar is costly we decided to make the investment because the lumber will last longer and will require less maintenance, repairs, and replacements (plus it smells so good!)
Plastic wire was chosen because it is less expensive than metal wire and it is easier to work with. It also is rust proof and easy to replace. This plastic is incredibly durable against the elements and would be very difficult for an animal to chew through. The holes of the plastic wire are definitely large enough for insects to pass through but we like to encourage pollinators in the garden and we watch closely for insect pests. If garden bugs become a problem we can easily cover the hoop tops with screen to protect against insect invasion.
We stapled wide strips of clear plastic sheeting down the length of the top of the hoop covers to help protect against hail and violent storms. This was a reasonably effective way to protect against weather if we happened to be away from home when a storm hit or were unable to cover the beds in tarps in time.
The hoops tops can also be covered completely with heavy clear plastic sheeting to make your raised bed into a greenhouse. Last year we did this for tomatoes, peppers, and cucumbers and found it to be quite effective! Remember to cut out a few spots in the plastic to create ventilation. This design is simple and easy to adjust to your personal preferences and needs!
- 2” x 6” x 8” Cedar Boards, Qty. 15
- 4” x 4” x 8” Cedar Posts, Qty. 2
- Galvanized Screws (3.5′, 2′, and 1′)
- 2” x 2” x 8” Wood Strapping, Qty. 6 – 7
- 1” x 2” x 8” Wood Strapping, Qty. 2
- 3/4“ PVC Tubing (sold cheapest by 100’ roll)
- 4’ Plastic Fencing
- Exterior Hinges, Qty. 4
- Eye Bolts, Qty. 4
- Zip Ties
- Lightweight Rope (such as nylon)
Instructions for Little Farm’s Raised Bed Garden Box
- Cut the two 4”x 4” 8’ cedar posts into six sections measuring 32” each. Each side wall will require three posts.
- With each side wall lay out the three posts and then place the 2”x 2” 8’ cedar boards over top. Each long side will require six cedar boards stacked three high. Screw the cedar boards into the cedar posts using 3.5” galvanized screws.
- Cut three cedar boards in half to allow for six 4’ pieces. These will be the end walls.
- Stack three 4’ cedar boards and screw on two 2” x 4” x 16.5” boards to hold the end wall together. Position the 2” x 4” boards to allow a 5.5” gap from the ends. This will allow the end wall to meet up with the side wall.
- Cut four 2” x 2” 8’ strappings 1.25” to create the base sides of the hoop tops.
- Cut two 2” x 2” 8’ in half to create the four end pieces of the hoop tops.
- Screw the 4’ end pieces to the base sides.
- Cut scrap 2” x 2” strappings at 45 degree angles to create diagonal supports and use them to brace the hoop top frame base.
- Attach two exterior door hinges to either the frame base sides or end pieces (depending on which way you want the hoop top to open).
- Cut out four pieces of 1” x 2” strapping at 45” to create vertical supports. Screw them into the middle of the end pieces.
- Take a 2” x 2” 8’ strapping and screw to the vertical supports (you may need another person to help balance/hold the top piece until the PVC hoops are screwed on).
- Cut 3/4” PVC tubing into 10’ pieces (total of 6 for the two tops). Screw each 10’ PVC hoop section in the base sides and the top strapping at the ends and middle of the hoop top base.
- Cut the 4’ high plastic fencing into 10’ long sections. Drape the 10’ sections of plastic fencing over the hoop tops. Attach the fencing by stapling the fencing to the base sides and using zip ties to the PVC hoops.
- Cut out the plastic fencing to fit on the ends and attach with zip ties and staples.
- Prepare the ground with a rototiller. Ensure the ground is level.
- Mark out post holes by laying out the side walls and marking the positions with surveying paint.
- Dig post holes to the minimum depth of 15.5” (make sure to call before you start digging and mark utility lines).
- Place side walls into the post holes and check positioning with a tape measurer, a 4’ level, and a framing square.
- Screw the end walls to the side walls.
- For extra vertical support of the side walls, cut two 1” x 2” strapping at 45” and screw one on each side of the middle posts. This will help ensure the middle of the garden bed does not wow out.
- Attach the hoop tops to the garden box by screwing the hinges on.
- Optional: Add eye bolts by attaching one to the hoop top frame base and the other to garden box itself, lining the bolts halfway along the length of the box opposite the side where you have installed the hinges. Simply add a length of light rope by tying each end to the eye bolts at the desired length to allow the hoop top to hang open via suspension but preventing them from touching the ground as they lay open.