Building wicking garden beds was a new thing for me. The idea of this self- contained raised bed is that it saves a lot of water through capillary action by supplying water from the bottom up.
Some of the benefits of wicking garden bed:
- It prevents evaporation
- drainage during heavy rains
- tree roots don’t reach soil
The timber for the garden beds was ordered from Dovetail Timber in Tasmania. Very solid 250 x 160 cm frames stacked together reached 60cm of height.
For this wicking garden bed plan I simply leveled the surface of the ground with a shovel.
Apply protective coating for the wicking garden bed frames with protective oil (Description of Intergrain Nature’s Timber Oil).
The parts of timber that are against and under the ground a stronger protection was used. (Description of Diggers Eco in-ground Timber Protecta)
Before you start applying coating to vertical corner post remember to round the sharp edges and splinters with f.ex sand paper. This way at the bug nets will stay in better shape for longer.
Place the wooden poles to each corner and center of the short edges. Screw them to the frame using screws and L-brackets. I dig small holes for the vertical posts and buried them 10cm deep. Stomp the earth tightly around the poles.
Drill hole to the corner where you wish to have the water outflow of the wicking garden bed. First drill a bigger hole for the plastic nut and then a smaller one for the hollow plastic bolt.
We found that by placing an extra plastic nut inside the frame the overall pipe system felt more solid. Like any phase of the project there are many ways of doing things. This one seemed like a good idea.
The drill sizes I used were slightly too small so some tweaking was required for the overflow pipe to fit the hole.
Cut pieces of geo-textile large enough to cover the bottom of the frame. I used staple gun to attach the textile to the timber. It made other phases of the project easier to do. The idea for geo-textile being on the bottom is to protect the water reservoir from getting punctured by small stones or roots etc…
Placing the plastic water container / reservoir takes time and is quite annoying. It helps to draw lines where each side is suppose to go and mark the corners to make this part of the job more straight forward.
Cut a hole through the geotextile and plastic tarp so the water outlet reaches the inside of the water container. Clean the gaskets, the plastic and glue everything together. Apply just the right amount of tightness so that everything glues together nicely. Who knows how tight is ´just right´…
Fill the plastic water reservoir with 6mm river pebbles to the top level of the first long edged timber. Almost a 1m3 of pebbles was used for each wicking garden bed (20cm height).
Try to avoid letting the pebbles fall into the drain pipe and overflow pipe.
Cut the excessive plastic away and level the pebbles.
Install a new layer of geo-textile on top of the pebbles. Try to cover all the spaces between timbers. This way the soil will not accumulate so easy between the timber. I used quite a few staples to put the geo-textile nicely. You can also use short nails.
I filled the frames with fresh and old hay, mushroom compost (1m3), soil that was removed while leveling the ground, old chicken poop soil and coir. What is your weapon of choice?
If you have any questions of comments you can write on the ‘comments’ section.