I'm planning on building a wicking bed this weekend out of some old timber I had laying around under the house, some left over agi pipe & PVC pipe.
Only have to buy the plastic, gravel and any fixing hardware and all should be done nice and cheap.
I've got some soil to use up from a good sized hole I dug during the xmas holidays for my fish tank
(stay tuned for that one). I’ve been sifting out all the rocks and cr@p with one of the trays out of the can-o-worms worm farm, it's taking a while to sift it all but the soil is so nice now.I'll top up the rest with coco coir, manure, some of my own worm compost and whatever else I can get my hands on.
Size should be about 2500 long by about 700 wide and around 600 deep. The timber I'm using is (I'm guessing here) around 20mm thick.
Couple of questions:
1. What sort of pressure should I expect from the soil on the longer sides at around 450-600 high? (I plan to dig in one end as my yard has a slight slope to it). Don't want any bowing when they are full!
2. Can anyone see a reason why a couple of old bed sheets or beach towels wouldn't work as the barrier between the rocks and soil? I'm not planning on buying new shade cloth and then cutting it up just to do this job, when I've seen on the web where someone used old carpet and found it did the job quite well.
A few other things I can/may do are, divide the bed into 2 or 3 sections (across the width-700mm) to allow for extra support along the entire length. Also I'll be using thicker sections (from memory /guessing around 70mm square,) for the corners. Depending on their length, they could be dug into the ground for extra support.
I'm planning to add a few buckets with holes in the bottom and using them as mini worm compost bins and seeing how they go. Almost like what mornings is doing but without the sump and pump
(ducking and hoping that one sneaks through to the keeper untouched 
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