"Ivan McDonagh" wrote in message
7.67...
SNIP
My question is, given that I can afford sufficient reticulation and that I
can get copious amounts of lawn clippings for free, would it be worth my
effort to place a reasonably thick layer of clippings over the sand, keep
it damp so that it rots (without or without the help of whatever worms can
live in pure sand), dig it in (using a rotary hoe) and repeat?

Mixing it all together will only do good to the sand. The clippings are
organic matter, and will provide some nutrients to the lifeless sand.

I expect it will be at least 3 months before I can get the chook poo in
the
quantities required which means I should be able to dig in at least 3
layers of reasonably rotted grass clippings. I am thinking that a covering
of fresh clippings to about 300mm (12 inches) will be enough to encourage
fairly quick decomposition but not so deep as to encourage acidity and bad
smells?

Still mix it all together. You will get some smell from the clippings, but
turning it all over every few days will help it rot, and avoid smell.
Don't overdo it with the chook poo. I wouldn't go any stronger than 1 part
chook poo, 2 parts sand/grass mix. Even that's too strong, maybe 1/5th chook
poo would be better.

If this seems like a good idea to those who know, my plan is, at the end
of
the 3 or 4 months, to place a good thick layer of chook poo on the
sand/grass mixture and dig that in straight away - obviously keeping the
whole thing reasonably moist all the time.

Don't put it too thick, as mentioned above.

After the chook poo, add the clay, dig in well and then continue with
layers of grass clippings and more chook poo. At this time I should be
able
to get some good hot composting going as well at the rate of 1m^3 every 9
or 10 weeks. This, of course, will be used as a mulch at the end of the
process.

The grass sand and chook poo will be your hot compost, or you can get some
from elsewhere to add?
If it's the first don't bet on having really hot great compost. Other stuff
would be needed, such as sawdust and other organic material like leaves,
mulched leaves, etc. If it's the second mentioned, then Adding compost would
be good.

The figures I think I'm looking at are about 2 tonnes of clay (for a
100m^2
garden area), about 40m^3 of chook poo and about the same of grass
clippings.

That's a hell of a lot of chook poo. Roughly, that is 40 bobcat buckets of
poo and 40 of grass clippings. To give you an idea, again roughly 4-5 bobcat
buckets of soil fills a small dyna tipper truck (2 or 3 tonne truck).
Over a 100square metre area that will raise the ground level by approx 70cm.
It is too much chook poo by far. The amount of clay you would want to add to
that 100square metre area would be enough to raise the gl by about 20cm, and
then dig it in. Maybe add the same amount of grass clippings by size, not
weight, then probably 5cm high layer of chook poo at the most. No, actually
half that.
With all the clay, you will want to add some clay breaker or gypsum to it.

I understand that the garden will be a bit higher at the end of this
process than it is now but that's not a problem since it is well below the
desired level already.

Ok, so I read that bit now :-). I would possibly look at getting some clean
fill for the area first as it could be cheaper, then look at improving that.
The way you are going to do it may be costly, and the pH may need correcting
big time at the end of it all.
Really the chook poo can't be used as bulk for the clay and soil, it will
just add nutrients. The grass clippings will help, slightly, but that clay
still has to be broken down with gypsum.

Sorry to keep coming back with almost the same questions but it's
important
that I do this right as well as cheap.

That's fine, and good luck with it. My advice is my opinion from experience
of working with clay, chook poo and grass clippings on a daily basis
(almost) :-)
Seriously though, work with the clay and sand first. Plants will grow in
that if it's broken down well. Then the clippings will add organic matter,
then at the very end lightly dug in chook poo, then finally plant a couple
of weeks later.
TIA

Ivan.

ps I also understand this is going to be time consuming in terms of
letting
nature take its course. I'm hoping to be able to plant out the garden
October/November of this year.