I've never made a wall, but I have made some fairly large pieces ...I think your wall would work. You can soak old towels or burlap in water, put that over your wall, wet it down real good, and keep plastic over the top to allow it to cure slowly.

Sorry, I'm not sure about the lime, but I'm thinking that vinegar water would help take care of that. Do you have a misting pump sprayer?

Hopefully, someone with more smarts than I will post. But, I say give it a try.

Hi Heather
The lime might be a problem for small acid loving plants planted close to the tufa this year but not for long.
We have tons of new cement retaining walls in my area (mountain goat country)and they don't seem to effect the plants at all.
If you have a few old blankets and a plastic painters drop sheet that should keep keep your wall plenty moist.

I was wondering if there was some particular reason that you wanted to use tufa instead of straight concrete? Regular concrete would be stronger, and less susceptible to being bumped & run over with a cart or wheelbarrow, for example. If you were thinking that it might not work as you expect, and that you might have to tear it out, it WOULD be lighter to dispose of.

You might also consider the use of a form of lightweight concrete, using perlite in place of sand, with no organic material. It would be lighter than regular concrete, and stronger than tufa.

If your terraces would be straight, it might be faster to just set up temporary wooden frames (oiled for release, & pegged in place) and shovel the mix in, let it set, remove the frames and put them in the next section, and keep moving along until you finish. If the terraces are to be curved, I wonder if Benderboard would be strong enough to use as the frame? (Dig a trench long enough for the Benderboard lengths, line with a sheet of plastic, lay Benderboard in it, fill with water, weight down boards with bricks until wet.)

This is all just theory, based on my mental workings of my plan to build lightweight concrete garden beds of the tip-up variety.

If you do it, it would be nice to see photos!

Sue

For curing in the heat, I would use a sprinkler and wet down the whole area as soon as your borders had set, then cover with plastic, holding it down with rocks or burying the edges.

Sue

What about using blocks? Debzone8 did some awesome blocks to retain her raised beds! Check out her album. She even shows the mold she used.

I've done a few to replace the plastic edging on a low bed and plan to do more to make some raised beds. You can take a looky if you'd like.
http://photobucket.com/albums/b394/Loren_/Hypertufa/

Good luck and post pics when you get what you want!!
Loren

Here is a link that might be useful: Deb's AWESOME blocks

Yes, I saw the block photos, and they were great -- my only concern is that the ground I'm trying to turn into a bed is so ragged and uneven (hellooo, ghetto garden!) that small sections of bent wire seemed like an easier framework to keep the wall touching the ground all the way around and also roughly level on top. I'm going for a roughly oval "pod" shape, so I don't think troughs would be the way to go -- I also wouldn't know how to get them level with the terrain.

So, wait -- concrete weighs less than hypertufa? I was thinking plain concrete wouldn't look as nice and natural, but I didn't realize it would be lighter ... is it significantly easier to deal with, or more of a six-of-one type of thing? I imagined concrete would be more liquid in consistency and therefore harder to sculpt around the wire.

Thanks,

Heather

Heather
LIGHTWEIGHT CONCRETE (where part of the sand is substituted with perlite ) is lighter tham regular tufa, as Sue mentioned. Read her comment again.

Actually, several professional websites say that they have used ALL perlite and NO sand, without any loss of strength. I haven't tried that yet. I'm not sure if they use perlite of all one size, or a mix of sizes to fill in the tiny gaps in the mix to make it more dense. Adding some silica flume might help with strength, too, but many people don't want to give away all their hard-won secrets.

YOU are the one who determines how much water is added to any mix. I know you've seen concrete "poured", but that kind of pourable mix is too liquid for the way we mostly use it around here. It's okay for 4" thick slabs, but not for what we do. Just like you would with tufa, you add water carefully so it doesn't get too sloppy. More water than you need will weaken the concrete, as will not enough.

In fact, I would say that nearly all the rules that apply to tufa (with the exception of the addition of organic ingredients) also apply to concrete (regular or lightweight). You want a fairly stiff mix (relatively speaking), that is neither too dry (crumbles when you squeeze a handful) nor too wet (drips, or slumps too much). A test handful that you squeeze should retain its shape well, but still be malleable enough to do as you want.

Before you start this fairly large, complicated project, I hope you try a few small experiments of a similar nature. Since you're using mesh, form a section like you will be doing in your project, and fill/apply the mix. Discover what kind of mix is best for YOUR project. See how it handles, and if you should be doing something some other way, find the easiest tools to use for packing and shaping. What you THINK should work doesn't always happen, and you have to change your plan fast. Try to do it on a small experiment rather than a big project. Discovering a mistake with a wheelbarrow load of mix that's ready to go can get you peeved in a hurry.

Besides, then you have to stop and dig a big hole to dump the mix into.....

Sue

Hi Heather
In your location south California you can get away with most anything.
If you want the rough stone look use lots of peat.
If you want light weight use vermiculite and or perlite in place of sand.
You could easily get away with almost any combination of the above provided at least 1/5 to 1/4 of your recipe is Portland and you don't use to much water.
1/4 is stronger and sets up faster.
If you can find a company that sells ZONOLITE products you can get perlite and vermiculite that is made specifically for adding to cement to lighten it.
There is an additional bonus to finding ZONOLITE products. Not only are they far better than the garden center products they should be cheaper. In fact by volume they are even cheaper than sand.
So if you went
2 peat
1 fine vermiculite
1 fine perlite
and 1 Portland Don't add too much water and cure your wall carefully keeping it fully hydrated for a week to 10 days you should have an attractive wall that should last a good long time.
If you want to speed up the aging process and reduce the lime in the soil you can scrub your wall down with a wire brush and pickling vinegar after a day or two. The brush will pull out the peat and vermiculite leaving a nice texture and the vinegar will help along with neutralizing the lime.

Good luck, have fun in the mud, and don't forget to post pictures.

Wow - I've been lurking the past few weeks, trying to figure out how I might be able to do pretty much the exact same project!

In my case, the two determining factors are size (I need the walls to be thinner than block-depth since the garden is so small and there won't be room otherwise for paths, etc) -- and shape, since I need the "walls" to be curved and probably about 2" tall and I haven't been able to figure out anything else I could use as a strong enough barrier (normal garden edging isn't tall enough).

My two questions (well, at least at this point :) are....
1) What do you think would be best to make the "skeleton" out of if I use the "build the mix into chicken wire, etc" method...will chicken wire give it enough strength? my one idea was that maybe chicken wire or mesh around some form of lattice (like you see on the top of fences) would give it a little more strength - does that matter?
2) Several regarding concrete:
a) first, a really newbie question...what's the difference between concrete and 'tufa? -- Per tufaenough's post above, if I use peat, vermiculite/perlite and Portland, doesn't that make it tufa? or can I mix peat and verm/perl into "regular" concrete?
b) the even more newbie question..if I want to make lightweight concrete (adding in perlite instead of sand and peat to give it texture) what exactly do I need to buy (ie - do I still buy a bag of "Portland cement", is it a bag labelled just "concrete mix", or is there some other name I'm looking for at the bigbox store?)
c) And last - will concrete need to be cured in a different way than you've recommended above for tufa? (okay, that's really four questions, not two :)

Thanks, thanks, thanks for the help! Promise I'll post pictures (since I know I've got to get started soon - I'm in Seattle and I'm afraid the beds I have started will wash away come fall!!) Any and all advice is appreciated!

Hello Heather !
I'm building a raised flower bed myself almost exactly the way you described your wall. I have already laid about 30 feet and almost complete. My wall is 3" thick and 10" tall and pored it solid using thick corrigated cardboard as a form. I coated the cardboard with Thompson water seal before hand. My mix consist of 6,4,4,1, peat,sand, portland,& perlite. This mix has allowed me approx three days to carve the stone block appearance into the tufa after removing the form. I sifted the sand to remove the aggregate to allow me to cut into the tufa with a razor blade. This mix ratio yielded a very hard cast.

Does anyone have pictures of these projects completed? Bamatufa are you still checking this site? I would love to see your end prduct and see how it is working now.