How To Build A Rockery - Part 3
Author: Johan Nickson

The specially prepared soil used in constructing the rockery
consists of topsoil (or loan-based compost) mixed with grit.
This provides a bulky, well-drained mix, which holds the rockery
together and provides an ideal habitat for alpine planets and
flowers.

If your topsoil is fertile and free draining it can be used to
make up this special mix. On an raised bed, the quantity you dig
out for the foundations will be adequate. But if the rockery is
being built on a flat site, you will need to move a small
quantity of topsoil from elsewhere in the garden. Alternatively,
order a 50kg bag or proprietary loam-based compost from your
local garden centre.

If your solid is heavy loam or clay is is best to cart it away
and use a proprietary loam-based compost instead. You will need
about 150kg (three large bags) to complete the rockery.

You will also require 75kg of 6mm grit (chippings) The majority
of this is added to the topsoil or peat to make up the specially
prepared mix; the rest is sprinkled thinly over the completed
rockery to provide a neat finish and to keep the weeds down. Two
types of grit are available; gravel and limestone. Order the one
which blends the best with the stones you are using.

On soil which doesn't drain well you also need a barrow load of
hardcore to fill the bottom of the drainage sump. Rubble, broken
bricks and stones collected from around the garden are ideal;
otherwise, try a local demolition site.

Preparing The Foundations

Start by marking out the site using pegs and a length of
string. Do not bother trying to form perfectly straight lines –
they will not look natural once the rockery is completed.

Guidelines usually get in the way when you are digging, so mark
out the area by dropping a thin trail of sand around the
outside; then remove the pegs and string and lay them to one
side.

To provide adequate foundations, the bed should be dug to a
depth of 150mm. On a lawn, remove the turf first; this can be
re-used if you are installing extra drainage so stack it to one
side. Dig out all the fertile topsoil and place it in a large
heap as close to the edge of the hole as possible. If the
topsoil is clay or some other soil, which drains badly, remove
it completely to another part of the garden.

Once you reach the required depth, compact the soil in the
bottom of the hole by trampling it down with your feet; this
will help to prevent the rockery from sinking. On a site with
bad drainage, install the sump at this stage.

Now prepare the bedding material. Clear a space by the side of
the hole where you can comfortably mix the topsoil or compost
with the grit. It should be mixed in the ration of one part grit
to five parts topsoil or compost. Throw five shovelfuls of
topsoil or compost on the ground and one shovel full of grit on
top. Mix the two materials together thoroughly and then shovel
the mixture into the bottom of the hole.


About The Author: Johan Nickson is a big fan of gardening
http://www.powertooldirect.co.uk