The financially cheapest option for building raised garden beds is to use recycled materials. Of course its much more time consuming than other methods.
Step 1: Collect your materials
Accumulating sufficient timber could be quite time consuming, some places to look for resources would include people doing renovations, leftover timber from other projects, the tip, items put on the kerb for council clean up or freecycle.
Sort your timber and stack it near the site of your vegetable garden.
Step 2: Prepare the site for the raised bed
Decide the size and position of your garden bed. Factors that affect size include the timber that you have on hand and the site itself. I have some frames from a previous project that I am going to use on my bed to protect the seedlings from domestic and wild birds, so the width of the beds are determined by that factor. And since I have some recycled sleepers for the sides they will determine the length. Cutting the sleepers is not a task that I want to consider at this stage.
Once I placed the sleepers in position the uneven nature of the ground in that area, and the slope were highlighted. I used a spade to dig a flat channel where the sleepers and planks will be placed, the width of the spade. I cheated a bit by putting some stones under one corner so that I didn’t have to dig quite so much. The idea was to get the bed approximately level because water will run down hill and not soak in evenly, it will also wash soil and seeds down hill with it.
Some people will measure up when making a raised garden bed to ensure the result is perfectly square, but this is for aesthetics rather than function. Using recycled timbers means that they are not straight, and they are not flat, and when I dug the channels to get the sleeper more level I moved away from the original position. I saw no advantage in doing twice the digging, the veggies certainly don’t mind!
Step 3: Secure the sides of the frame
Using sleepers they are able to stand on their side unsupported, but they would become unstable and likely to get knocked over as the sides rise. When the garden is filled the weight of the soil will prevent the sides from falling inwards, so the sleepers just need to be stabilised from the outside.
The simplest method didn’t require me to drill holes for screws and nail, nor use any building skill at all. I simply used stakes and star pickets that are about 60mm long, and banged them into the ground on the outside of the sleepers; 2 per side.
The side walls of the beds that I made were made of recycled timber not wide enough to stand on the side unaided, but resting against the sleepers on the inside and with stakes holding them up on the outside they are quite secure. It was at this point that I measured and cut the wood for the sides that way the length matched for the positioned sleepers rather than a predetermined size.
Step 4: Finally, Raise the rest of the sides.
Once the stakes or start pickets were in place the remaining sleepers and beams were put in place. I have built beds that are currently 2 sleepers deep, the sides had more pieces of wood to reach the same height, as they were not the same width as the beams.
For the second bed I didn’t have as many sleepers, and not quite enough wooden beams to achieve the same height all around. This is the nature of a bed using recycled materials, and I may have to leave this end of the bed not as full until I find another beam.
Filling the beds.
Once the raised garden bed frames have been constructed, filling them with soil and compost is the next stage. I will cover this in the next article.
It is important to be aware that treated and recycled timber may contain poisons to preserve the timber. This poison can leach into the soil and be absorbed by the vegetables. Line the frame with plastic so that the chemicals stay out of your food.