We put a wheelbarrow load of compost in each wicking bed yesterday, and finished the job today. Each bed got another load and a half, then a bag of manure was shared between the two.
The compost was a bit gluggy, having been made out of our own clay dirt, so we went out of our way to lighten up the soil and bought in some vegetable potting mix. Each bed got 100L of that and 50L more of manure.
With that we were able to mix two tubs (42L each) of just regular dirt from the diggings in this spot. It was well mixed together and feels pretty good.
All it needed then was a layer of mulch on top to maintain a steady water saturation. There will also likely be some weed seeds in that local soil that the mulch will hopefully keep down.
It’s ready to plant, and the next set of pallets are being dismantled to continue the cladding.
The next step with the wicking beds is to leak-test them. So we filled them part-way with water.
This is the top half; it’s got a big lid in it for filling the IBC. It wasn’t screwed on properly, so it leaked. The levelling/emptying outlet also hadn’t been more than finger-tightened, so the plumber’s wrench came out to fix that up.
A couple of lines were marked for the top of the soil and the bottom of the soil/top of the reservoir, which lets us know when to stop filling it with perlite.
That let us cut the level indicator stand pipe to the right length.
Tipped all the water out, tightened the bits; value was had since R went and donned the wellies so he could jump up and down in the puddle so created.
It’s about 150L of water, so the special emptying function of the water level indicator was employed.
Onwards! Out came the perlite, and a bag-and-a-half went into each bed. Dust masks are essential for this stage.
We put geotextile over that. Bunnings sells 2mx6m lengths, which will do 3 beds. The geotextile needs to be about 2m square so that there’s enough to go up the sides with a bit to fold over.
The geotextile was folded over the plastic tub bit and inside the cage of the IBC. This keeps everything in place and doesn’t need any fasteners which will aid dismantling. The cladding will cover the folded-over cloth once it’s on.
Each bed will take about 4 wheelbarrow loads of dirt. We have some compost from the old pile on the former trampoline base, which has to be brought about 20m uphill. With steps. We put one load in each before calling it a day.
We can plant once we’ve filled them with dirt; the cladding for the remaining 7 sides will come as we get time to do it.
Eventually we’ll have six wicking beds up on the garage plateau, and part of the process is tidying the whole area up. We’ll also soon have a need for some dirt for rammed earth, so decisions were made to lower the level just a little bit before putting the wicking beds down.
As it turns out, the “back” (hill side) of that spot is quite a bit higher than the “front” (house side), full of rocks, and much harder clay to boot, so digging out the spot for the second wicking bed was a bit harder than for the first. Since the shou sugi ban will take a little while to complete for both beds, it was decided to site the second bed first, so that it wasn’t sitting around looking like rubbish.
A giant rock at the back won’t be coming out without machinery, so it’s forming the back wall for the second bed, with one corner going around about where the bricks are.
We made another frame, this time with legs 11cm shorter than the first frame, because the bottom half of the the IBC has an extra footing bit on it. Although it could have been taken off, there’s no need.
A trip down to Hermon’s Corner yielded a uteload of mulch for keeping the weeds down and sludgy winter mud out of our boot soles. A great deal of effort went into ensuring that the four footing bricks were all level and square to the house.
Ah. Now it looks like it’s there on purpose. And we got a nice pile of good-sized rocks for our wall-building.
Yesterday we got most of the way through the shou sugi ban process on our first batch of pallet wood. After washing it, we left it to dry overnight. This morning we got the tung oil out and oiled each piece, gave them a quick lick of fire, and then started putting a piece of cladding together.
Each side of a wicking bed will have its own cladding “fence”, so that it can be dismantled and handled by one person. There are two horizontal rails around the outside of the bit of IBC in the current bed, so we’ll “hang” the cladding off the rail and screw it into the frame leg to keep it in place.
Our cladding has three horizontal rails: one to secure each of the top and bottom of the cladding, and one to hang it. We nailed the end cladding bits on first, making sure they were square, and then took the minimal frame to the wicking bed to determine where to put the hanging rail.
After that we had to do some calculating about how to space out the cladding pieces. We measured the gap between the two end pieces, and determined that a 6-piece, 7-gap pattern would ensure a decent overlap between the two layers of cladding. We calculated how big each gap needed to be ((total space – 6xboard width)/7).
Each gap was 55mm, so we set up a fence on the compound saw and cut 12 little pieces from one of the crappy bits of wood that wasn’t good enough to become cladding. It’s important to use the same wood as is in the rear layer, so that the thicknesses are the same.
Why 12 and not 14? Just because one of the pieces of cladding was a particular width, doesn’t mean they all are. So once they were laid out we could measure the width of the last gap (a bit narrower), and cut special bits for it.
Then it’s just nails. Bang bang bang.
We hung it on the IBC/frame and it looks awesome.
We had enough wood from 2 pallets to make one side. There was a bit left over, which means the same will do the two longer sides on this IBC. We’ll use the leftover bits to make a little shelf on the top of the cladding, which will keep water out of the end grain and cover the rather messy cut that was made to get the IBC in half.
To raise the wicking beds up to waist-level, we need to put a base under our half-IBCs. We’ll use pallet wood for that.
On pallets, there are three relatively thick pieces of wood that form the inside, three or four thinner pieces on the bottom for rigidity, and about 8 even thinner pieces to make the top.
The three thick pieces, joined together, will make good legs for our base. The wider pieces on the underside will make good rails.
Our IBC was 1m x 1.2m, measured from the outside of the cage. They’re not all the same – some are squarer – but this was the one that fit into the back of the ute between the wheel wells.
The nicest pallet with the thickest wood was 1.16m square, which makes the bits of wood just the right size for the IBC, with one side cut a little shorter.
The top half of the IBC is 51cm high, and working height is 90cm, so a 39cm leg is called for. Using the three thick cross-pieces, we can cut each piece into 3 pieces each 38cm long, giving 9 pieces in total. We join two together to make a leg, leaving 1 left over.
With 4 equal legs, we cut two pieces of the wide flat stuff to 1m and joined them to two legs each to make rails. Then we joined the two two-legs together with bits straight off the bottom of another pallet to complete the rectangle. With the width of the rail taken into account, we needed just a little gap at the edge of the leg to make the total width to 1.2m.
One of those rails is cedar, which became apparent when it was cut (mmm smells yummy). The rest is pine, and the whole structure is very light and one person can handle it. We won’t bother treating it, because the whole thing will be behind the cladding and not exposed to the weather.
We’d done a bit of digging earlier to prepare the ground, and there was a bunch of weeds removed from the spot behind the frame here. The big boulder had to be moved, because it was going to be in the way (right where the back left leg of the frame is now).
I wasn’t quite clever enough on the calculations, though. The IBC’s frame sits on the short end rails perfectly, but I forgot to account for the fact that 1m was the outside measurement and it’s out by the width of the rail. The rail at the right here has to be moved across about 15mm so that its end lines up with the outside of the other rail. It’s important to get right, because other bits of the structure will join onto these bits.
Update: all fixed. The ground wasn’t quite flat, so efforts were made to tidy it up. One thing I’ve learned is that bumps in the ground don’t flatten themselves! Shou sugi ban next.
We’re going to raise our IBC wicking beds up to standing height, which means some kind of framework underneath them. Since we’re going to use shou sugi ban-treated pallet wood to clad them, we might as well use the rest of the pallet to make the framework.
Old rubbish pallets are free. Plenty of businesses are happy to give you their old ones – it saves them a trip to the tip. Just be sure to ask, since they’re often stacked with ones that are still in use.
We were able to fit four at once in the back of the ute.
We were sure to get ones that weren’t painted, so we’re not gassing ourselves while we treat the wood.
Each of the pallets we got was different to all the others, with a whole mix of length, width and thickness. Most are pine, but one of them was some kind of hardwood – spotted gum, I think. They all had different nails, which were all pulled out. One had thin staples, which were cut off with the angle grinder. It was a very lightweight pallet, but the wood will make great cladding.
A spot of hammer-bashing and they’re all ready to be remade into something awesome!