Leaf curl horror

The spring so far hasn’t been very springy; it’s been wet and cold. The peaches and nectarines have all come out with really bad leaf curl fungus. Despite this little guy emerging on one of the peaches we don’t hold out much hope for any fruit.

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The nectarines are looking really bad, too, after putting out some nice flowers. Actually concerned that they might not survive.

First wall prep

We’re happy enough with the rammed earth test cylinders we made last week. After a day drying they went rock hard, and are certainly sturdy enough for the first job we want to used the rammed earth for.

We posted the idea a little while back, and given that we don’t need planning permission for such a small wall, we can just go ahead and do it. Here’s the vision:

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The picture is not entirely accurate: the cladded wall at the rear is a little further back, the rammed earth wall is a little closer to the house and not so wide, and it doesn’t extend beyond the side of the house just visible on the right hand side of the picture.

The first thing is to remove the garden bed that’s currently in that spot.

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The lavenders haven’t looked any good for ages, and the bulbs are done flowering. They won’t like being transplanted, but they’ll be back next August guaranteed.

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We need to bring the base of the wall down to the undisturbed dirt level, which will be under those bricks. So we dig up all the dirt and cart it down the hill. It’s not consistent clay like you’d find deeper down, so we can’t use it for the wall itself.

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We also took out all the red gum sleepers. We wanted to save them, but there was only one or two that can be re-used. The rest were half rotten, which makes me a tad nervous about the rest of the retaining around the yard. Some of it is starting to fall to bits, and I’m guessing that we’ll have to get onto these new walls with a bit more speed than what we’ve applied to the project so far.

The garden bed was cleared out in an afternoon, after the morning was spent procuring a post hole digger. The following morning was spent cutting the grass, since rain was expected in the evening and it’s a lot easier to do when it’s dry. Once the maintenance jobs were out of the way we could get back to measuring out the wall.

The deck is going to be 1.6m around this and the adjacent side of the house. This width marries up with the width of the stairs we’ll be putting in to the lower garden, a couple of which are already in place. So we put some stakes in the ground 1.6m away from the house.

We’ll make this wall 30cm thick, which is way too much to carry the load of half a deck and whatever we might put on it, but which is a good balance between ensuring load carrying capacity (a thicker wall) and reducing the amount of material we have to prepare to put into it (a thinner wall). More stakes 1.3m away from the house, requiring us to remove some of the pavers.

We line it up with the end of the house and the nail we put into the house to mark the end of the garage all that time ago. Total length is 5.2m. We set some string down the middle and measure out spots for 5 piles. The piles will go down into the ground a short distance to anchor the wall against the soil and water pressure that will be exerted on it from the driveway. It’s unlikely that they’re actually required – I haven’t done the engineering for this little wall – but it’s all about practicing our techniques at this stage and a bit of over-engineering here is not going to be wasted effort.

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Finally all that’s left is to calculate how much dirt we need. We set the laser level up on the floor inside and shone it out the window. That allowed us to calculate a height from the ground to the top of the floor inside, which was 47.5cm. The top of the deck needs to match that. We take off 10cm for the concrete foundation, 7.5cm for joist bits that sit on top of the wall and the thickness of the decking, leaving a 30cm rammed earth wall. The volume of the wall is then 520x30x30cm or 468,000cm3. That’s 468L. From our cylinder experiments we know that compaction around about halves the volume of uncompacted dirt, so we need double the amount in the compacted wall of uncompacted material –  936L. That’s pretty close to 1m3. Our big dirt-carrying tubs are 42L when full, so it’s a little over 22 tubs in total. Or 11 wheelbarrows, since 2 tubs fit in the wheelbarrow. Which is pretty close to a ute-load (our mulch-carting exploits provided the information that the ute holds around 12-13 wheelbarrow loads of mulch).

The 5 piles will be 15cm in diameter, and go down the length of a standard bit of rebar minus 5cm which will extend into the foundation. That depth is 55cm, so each pile will contain ?x7.5×7.5x75cm or 9,719cm3. That’s 48.6L in all 5 piles. The foundation slab will be 520x30x10cm or 156L, not counting that the rebar inside it will reduce the amount of concrete we need to make. One part in 7 of that amount is 22L, which when added to the same proportion in the piles gives us 29L, the amount of cement we need to buy for the foundation. That’s a little bit bigger than a standard bag of potting mix. Interestingly, cement is sold in bags of a specific weight, not volume, despite requirements for cement being pretty much universally volume-driven. Boral helpfully tells us that 108 20kg bags give us 1m3, which means that we need just over 3 bags for our 29L. If we also put a bit into the rammed earth part (2% of 936L), we need 5.2 bags.

Rammed earth test cylinders

After talking about it for possibly decades, now the rammed earth begins.

Step 1 is to test the suitability of your local soil. We did a soil grain size test earlier and found that around here it’s basically 100% clay. We also worked out that adding about 25% sand should give us the consistency we need for a good strong wall. So we’re setting out to create some mixes of local clay and imported sand and maybe even a bit of cement to see which is the best mix to use.

Using the big pile up near the wicking beds, we sieved some dirt first to get a decent grain size that will mix easily with the sand. The dirt is all the same stuff, but some of it is dry, some wet, some broken up and some not. Unless you live on top of a sand quarry you’re never going to be able to just dig dirt out of the ground and expect it to be good to go straight away.

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The sieve is a 5mm mesh

We’ll use 100% local soil on the first one to serve as a control/baseline. We also used the first one to figure out how much soil we need to make the cylinder. It was about 17 trowels, which we upped to 20 to make working out the proportions easier. We added two “hoses” of water to each 20-trowel pile of dirt. A “hose” in this case being water that is under pressure in our 30m hose after the tank pump has been turned on and off. Turn the pump on until pressurised, squirt the hose until pressure is lost, repeat.

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It’s not really accurate, but the soil doesn’t start out at a consistent moisture level so there’s no point trying to finesse it.

Mix it up and make a little ball. Drop the ball from a consistent (waist) height.

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The amount that the ball flattens and the size of the cracks in the side show you whether you need to add more water or not. This one is OK.

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The form is 200mm of 100mm diameter PVC stormwater pipe

Our fancy rammer that we made earlier turned out not to be useful for this. It expanded after being let out of the form and now it doesn’t go back in again. It was also really unwieldy for such a small form so we cut the ends off a nice round branch and used that instead.

We started out using the mallet to aid compression, but it unnecessarily complicated the process. The dirt wants to travel up the sides of the form anyway, so it’s never going to be consistent. We ended up just using arm power which is probably better anyway, as that’s what we’ll be using to make the walls.

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The form wanted to creep upwards as we rammed, letting dirt squeeze out the bottom. So forms need to be attached to the ground below when doing the real thing.

Gently easing the form off…

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The grey bit is some concrete that came off the big rammer while we were seeing if it would go back in the form. I’m thinking that the big rammer will be less useful than hoped.

Well, that clay is very sticky. We don’t want this happening when we take the forms off the walls.

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The dirt stuck more at the top of the form. It probably isn’t rammed as well as the rest of it, since it’s hard to really pound the top bits without the dirt flying out everywhere

For the next round, we took 5 trowels of “builders” sand and 15 trowels of local clay. The sand is relatively fine, and my first impression was that something coarser was needed to balance out the very fine particles in the clay.

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We can get this stuff by the truckload when the time comes

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Working with the sand-impregnated soil was much nicer than with the raw clay. It wasn’t nearly as sticky and compressed a lot easier. It really makes a big difference.

We also put a bit of oil inside the form and it came off without bringing half the dirt with it.

Next up we added 25% white beach sand, which we were expecting to change the colour of the mixed earth but didn’t make a noticeable difference. The grain is a lot coarser and the final mix didn’t feel as robust in the hand as the builder’s sand.

Then we did the builder’s sand again, but added half a trowel of cement which gives around about a 2% cement mixture. Our assistant made signs so we know which is which.

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In all the excitement it was dinner time by the time we were done, and no-one had even thought about dinner yet. A quick trip to the wicking beds and we had lettuce for Caesar salad – good times!

Second native bee

This guy got caught up inside against the window. It seems I’ve developed an eagle eye for bees, as I spotted him from across the room and he’s only about 10mm long.

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Research indicates he’s a member of the Leioproctus genus, but which species is anyone’s guess, maybe Leioproctus ignicolor

New shower handles

R has started washing in his own bathroom, and it was high time the taps in there were modernised like the others in the house. It didn’t take too long to swap them over, but as usual the old ones were not only screwed but glued into the wall, which made for a good helping of frustration getting them off (and some scuffs on the tile paint).

The big orange shower head is a silicone thingy from IB Rubinetti that has been sitting in the cupboard for about 4 years: it’s design means the water exit point is quite a bit lower than where the pipe comes out of the wall, so it needed the goose neck pipe to make it practical.

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October veggies

Here we are in the second month of spring and the weather has been atrocious. Constantly overcast, storms, cold and buckets and buckets of rain. The veggies haven’t gone into full profusion without much direct sunlight.

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Lettuce is harvestable, but still small
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Spinach has been disappointing – older leaves are dying before they can be replaced with newer ones. Maybe we just need to harvest a bit more vigourously (or at all)
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Shallots in the middle, punnet onions on the left and leeks on the right. Still babies.
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Garlic on at rear left is going OK, onions have mostly sprouted pretty well. Spring onions on the right had a fairly poor survival rate from transplanting and the patchy nature of their demise indicates something might be getting in there and wreaking havoc
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The potato bag needs watching. The plants on the right are probably ready to have more compost piled on them, while the ones on the left have only just surfaced. We’ll need to wait for them to grow up a bit before raising the bag sides