levelling - dig down or add up?

 
Hi I live on a slope and after my two patio slab depth patio area my
garden
slopes down from the right to the left quite considerably. It
means there is not
much garden for the children to play in.

I therefore want to level it out. Question is, do I:

1 - build up the left to bring the whole garden level and turn my 6ft
fence in
to a 3 ft fence as a result.

2 - dig down the right to level it with the left and create a step down
from the
patio to the garden. This keeps the 6ft fence and therefore the
privicy.

Not sure if it matters but eventually I'll be making the patio much
bigger.

Thanks




--
mphowells

 On 6/27/2009 3:54 PM, mphowells wrote:

I would do both.  Cut down on the right and use the "spoil" (the dirt
that is dug out) to fill in on the left.  This means less cutting and
less filling.  This is how tracts of homes are graded.  There will be a
boundary separating the cut and fill; this is known as the daylight line.

Till on the right enough to prepare the soil for planting.  Till on the
left at least a foot or more into the existing soil to blend the fill
with the old soil.

You might want to plant some deep-rooting shrubs or some trees on the
left to stabilize what you have done.

You might want to check with your local city or county to make sure that
what you are doing is legal.  Where I live, if the cut or fill are
noticeable, a grading permit is required.  Before the county will issue
a permit, they require a geologist and a geotechnical engineer to
prepare a soils report and grading plan.  Then a civil engineer must do
grading drawings and complete a storm-water runoff mitigation report and
a erosion control report.  (Those two reports are required by federal
law.)  The county's permit fee might run $5,000 or more to cover the
costs of having county engineers review all reports and plans and then
inspect the work; I think the minimum fee is $1,000.  (All this is from
personal experience of having a failed slope repaired.  See my
<http://www.rossde.com/garden/garden_back.html#hill> .)

Of course, your own local authorities might not require a grading permit
at all for minor leveling of a garden.  However, be careful that you do
not wind up directing runoff onto neighboring properties.

--
David E. Ross
Climate:  California Mediterranean
Sunset Zone: 21 -- interior Santa Monica Mountains with some ocean
influence (USDA 10a, very close to Sunset Zone 19)
Gardening diary at <http://www.rossde.com/garden/diary>

 David E. Ross wrote:

  That is exactly what I've been doing, didn't know the terms! I've
terraced my garden and a friends who has a much steeper slope.

   A few hints.

Get a good mattock and loosen the soil with that, rather than a shovel.

   You may find that when you dig down that the soil quality
deteriorates. You may wish to do some dirt sorting.

   I'm going to reread David's post to pick up some new ideas!

   Jeff

 On 6/29/2009 9:24 AM, jeff wrote:

Sorting surface and subsurface soils might not be necessary.  An old
gardening practice is to double- or triple-spit the soil.  "Spitting" is
digging to a depth equal to the length of tines on a spading fork (which
is definitely NOT a pitch fork or hay fork) or the length of the blade
of a spade.

To improve the soil, you spit a trench, piling the soil on the side away
from where you plan to dig the next trench.  Then, you spit the same
trench an addition depth, piling the soil next to the first pile.  A
third spitting would be nice but not always necessary, depending on the
soil.

Next, you spit a new trench not only parallel to the first one but
actually in a way that merely widens the first one.  The new trench is
one spit deep with the surface soil piled on the bottom of the first
trench.  Then soil from the second spitting of the new trench goes into
the first trench on top of the soil from the first spitting of the new
trench.  If you triple-spit, the bottom third from the new trench
becomes the top layer of the first trench.

Now you start another trench, filling in the second trench.  Etc, etc,
etc.  When you finally spit the last trench, the piled up soil from the
very first trench -- in the proper order -- fills it.  Soil amendments
can be added while spitting.  Phosphorus can be placed at the bottom
where roots will find it, but other nutrients should be withheld until
after plants are established.

This can indeed move the better soil down and inferior soil to the
surface.  The better soil might even be beyond the reach of the roots of
annuals and some shallow-rooted perennials and shrubs.  However, the
tilth is very much improved.  If spitting is done correctly, it might
not have to be repeated for many years.  (Of course, if shrubs are
planted, it will never be redone.)

Similar results today can be obtained with the use of a power
rototiller.  You till a single width of the machine for the length of
the bed.  You shovel the loose soil to one side.  Till the same area
again and again shovel the loose soil beyond the first row that was
shoveled.  Adjacent to the first area, till and use the result to fill
the first area; till again and complete the filling of the first area.
Etc, etc.  Amendments can be applied before each tilling; the rototiller
will mix them into the soil quite well.

To level a gradual slope, use a rototiller to triple-spit the high side
and double-spit the rest.  Just move some of the tilled soil from the
high side to the low.  If the slope is more than merely gradual, a
grading permit might indeed be appropriate.

--
David E. Ross
Climate:  California Mediterranean
Sunset Zone: 21 -- interior Santa Monica Mountains with some ocean
influence (USDA 10a, very close to Sunset Zone 19)
Gardening diary at <http://www.rossde.com/garden/diary>

 mphowells wrote:

You could do either or both.  First I would find out what the soil profile
is like in the area concerned.  If there is rock or plastic clay not far
down it is going to limit your options.  If you are going to cut and fill
what sort of material will this bring to the surface?  You want grass for
kiddies to play on.  When you have finished will grass grow where you want
it to?

Second before lifting a shovel plan it out, measure the area, take levels
and compute the amount of cut or fill required and the amount of soil to be
moved, it may be more than you think.  Further plan the drainage and
utilities.  Where does ground water and roof water flow now?  How will your
work change that?  You don't want to build a dam or hit a spring!

Are there any pipes or services under the area?  When the house was built
where was the rubbish heap, are you sure it isn't still there buried?

If you are going to bring in equipment how will it get in?  If you are going
to do it by hand how long will it take?  Do you need permission from local
government?

If you have no idea how to answer any of these questions then pay somebody
who does.

David