How to Build Affordable Raised Garden Beds

As planting time quickly approaches here in Alaska, I recently installed two raised garden beds in our quickly-expanding mini-farmstead. Raised beds are especially helpful in Alaska, as the beds warm the soil faster and warmer, allowing one to plant earlier and try warm-loving veggies. I’ve seen many different types of beds, but I was looking for something that would be easy, and most importantly, affordable. I had thought of using a variety of different lumber types including 1×12 cedar planks or two 2x8s stacked on top of one another, attached with 2x2s. After pricing it out, is was cheapest to just buy 2x12s.

Raised beds are difficult to work if they’re much wider than 4 feet. A 4 foot bed allows you to weed and work the bed from both sides without having to stretch out uncomfortably far. I made my beds 16′ long and 4′ wide. Because I was putting in two beds, I simply needed 5 2x12x16′ planks. (Make sure you don’t use treated wood, as it is full of sketchy chemicals.)

Before I go into how I put the beds together, I thought I’d give a quick overview of cost. Realize that these are Alaska prices and you might be able to do it for substantially cheaper.

Costs:

  • lumber    $65
  • topsoil    $35
  • wire          $5

Total: ~$100 per 4×16 raised bed.

I figure that if the cost doesn’t pay for itself in one season’s harvest, it certainly will in two.

 

Steps for Building the Boxes:

1.Cut boards to length and attach with exterior grade wood screws. I used 3 1/2″ decking screws. (Make sure your 4 ft boards butt up against the long boards so you end up with a full four foot wide bed!) You may also want to use something like Simpson strong-ties on the corners to prevent the boards from coming apart as the years go by.

I simply used 3 3 1/2" screws on the corners.

2. Level the boards. You may want to level your garden area before you put the beds together. My location had nearly a foot difference on level from one side of the beds to another, so it was easier to put the beds together first and use them to determine where I needed to dig out and where I needed to fill in. I propped up the boards with small pieces of scrap wood until they were level. That gave me a good idea of where I need to remove material and where I needed to add it. I simply used a spade shovel for this step, putting the beds back in place periodically to adjust my digging to ensure they were level.

3. Drill small holes every 4-5 feet. In order to keep the boards from bowing out from the pressure of the dirt, it’s important to brace the wood every several feet. There are many ways to do this, but I have seen people use wire with good effect over the long term. I drilled two holes on each board every 5.5′, drilling about 3″ and 9″ from the top of the board.

Drill holes avery 4-5' and 3" and 9" down from the top of the board.

4. Thread galvanized wire through holes, connect in center, and twist to tighten. By  threading the wire through either sides of the board and twisting it taut, the wire should hold the boards in place when filled with dirt.

Twisted galvanized wire keep the boards from bowing out.

5. Add your soil. I had chicken litter bagged up from cleaning the coop in the winter, so I spread it onto the bottom of the beds, hoping it will compost down nicely. I added my soil on top of that, but did not mix the litter in with my soil. Uncomposted chicken litter is far too high in nitrogen and will burn the plants and roots.

I put a couple inches of old chicken litter in the bottom of my beds

6. Mix in soil amendments. I added some fish and bone meal from Alaska Sea-Ag, and I plan after this growing season to get the soil tested to see exactly what soil amendments may be needed.

Finished raised bed ready for planting

 

Next up: How to Turn a Raised Bed into a Hoop House!

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