At my house, we have 2 major problems, Gophers and Moles. So one of our goals was to have a garden we could keep gophers and moles out of.
It was pretty crazy to actually catch both animals in my yard.
In addition to that, we needed a separation in our yard to identify where our 26 month-old son was allowed to wander and not. With that in mind we looked to raised garden beds.
Though wood is a common material, we've had termite problems in the past and chose to stay away from attracting them again.
Eventually we came up with a solution. We had put in a vinyl fence a few years ago and had a leftover piece that we had cut from a full panel.
With that piece in hand we sought out what the expense was.
Step 1: Big Picture Helps
A standard panel was $60 from Lowes, (plug) and had 11 vertical slats, meaning we could cut the panel into 2-slat pieces and have enough for 1 square bed with leftovers.
Making the corners turned out to be a frustration of sorts. How do you join two corners and still make it look good?
What metal material do you place in the bottom to keep the gophers and moles out?
Does it have to be metal?
Lowes apparently has broken or chipped panels regularly meaning they sold us one at half off, dropping the panel price to $30.
For the bottom, we chose to use Metal Lath, which came in approximately 28" x 96" pieces for around $8. With the final internal bed dimensions being close 67" x 67", the span would require 3 panels, i.e. $24. Yes we could've used chicken wire, but gophers and moles can squeeze through. Yes, we could've used welded wire project cloth, but we found that the prices were very close to just using the lath. We could've used expanded metal (steel) but one sheet was about $60 at the vendors in town I found.
For the corners, we chose to cut square vinyl posts into right angles. Since the 2-slat sides were 12" wide, the corners would need a 12" piece on the inside and the outside as shown in the pics.
That means 8 pieces per bed at a length of (2 pieces per corner/2 pieces per foot)*(4 corners per bed) = 4 feet. A single 8 foot post was approximately $20 and would make 2 beds. That's $10/bed.
Screws could be anything with enough bite to grab the vinyl and keep it together. You can use PVC adhesives though that can be very messy and even add a lot of cost. We used 8 screws in each corner and 6 screws along each side to attach the lath. To keep the joints together, you can use zip ties, weave bailing wire, any number of options. PVC glue cost us about $8 for the cleaner, prep and actual glue. And we all but used up the size of containers we purchased.
In addition, one thing we found was that the gap between the slats would become a frustration because of the inevitable "seeping" of dirt after rains, so we need to bond a strip of vinyl in the gap. The pieces we found were around $1.50 each for an 8' strip, so a total of $6 per bed.
Total cost of the bed: $30 + $10 +$24 + $6 + $12 = $82 (Super expensive, OUCH!)
But, it would match our fence (mattered to my wife but not so much to me)
AND it would last for a very, very, very long time. And probably outlast half a dozen wooden beds.
Plus the now vertical supports make for a very simple method of converting these into hot beds in the winter.
Step 2: Design, Measure, Cut
I used a radial arm saw to cut miter joints at the ends of my panels, though a sliding compound miter saw would work. You could cut these by hand hand but it would take a while because of the number of cuts needed.
To cut the square post, I set the saw at 45 degrees incline, rotated the head 90 degrees and fed the post along the fence.
Because the post is "sprung" when you make a cut, it will want to pull together after a cut, so to make it square, I place a 4x4 inside the post with planed shims of .25 in hardboard to create a support.
You could cut the post into 4 corners, lowering the cost but you also significantly lower your footprint in the corner for fasteners.
Another option is to use a table saw. As long as the "keep" corner stays against the fence, you shouldn't need an insert in the post.
Once you get the panels cut, and the corners in place, clamp with spring clamps.
Measure the inside dimensions of the garden bed. Transfer these dimensions to your metal lath, expanded metal or wire mesh. I used a 2x4 to create a straight line, but if you have a sheet metal brake, that would work best.
Step 3: Glue, Clamp, Drill
I used left over aluminum vinyl screws, though decking screws should work fine for assembling.
A change I would make to my next one would be to use treated lumber as a core in the corners. I would create the joint first then slide the panels over the core and then the screws would have a solid core to attach to.
Step 4: Sift Dirt and Add Nutrients
Not all soils need additional items, though to encourage strong plant growth and to ensure the right type of environment, i.e. nitrogen rich, fertilizers and/or compost can greatly improve the quality of the soil.
Make sure that you mix your soil such that the soil is well-suited for the plants you plan on growing.
Step 5: Plant Your Veggies and Go...
You can modify this concept several ways.
Narrow your beds, which means you can get more beds, though less square footage.
Make your beds shallower, and you effectively double your square footage, though you loose ground height, meaning you will have to stoop lower to work.
Add wood inserts in the supports and build "catwalks" to allow a support for leaning in the center without having to crush the soil.
We've built 2 of these so far and plan on building 2 more. Last year we planted spinach, swiss chard, sweet corn, bell pepper varieties and cherry tomatoes. We'll see what we get going this year.