as an alternative
to other paving systems
enables turf
establishment with load
carrying capacity and
minimal maintenance.
Unlike gravel and
sand, expanded shale is
able to absorb and
release water and
nutrients, which may
increase the nutrient
protection capacity of a
highly porous growing
medium.
TruGro® is only
1/3 to 1/2 the weight of
regular rock or sand
making it easier to
transport and install,
but it is heavy enough
to resist being washed
or blown away under
normal weather
conditions.
TruGro® is chemically
inert and completely
inorganic. As a result,
it will not compress,
decompose or react with
other agricultural or
horticultural chemicals.
It will not sink or
float out of a blended
medium, meaning it can
provide superior
aeration when used in
soil mixes, especially
if compaction is
required.
Expanded shale, a
gravel-size rock, helps
make clay soil easier to
work and improves
drainage. More good
news: You only add it to
the soil once.
But one amendment you
can add to new plant
beds is less well-known,
and it may be the most
valuable of all.
Expanded shale, a
gravel-size rock that is
pumped full of air,
aerates clay soil, makes
it easy to work and
helps it drain better,
says Steven W. George, a
Texas Cooperative
Extension horticulturist
in Dallas. Best of all,
you add it to garden
beds only one time.
"It is just so much
better; it makes it fun
to garden in clay," Mr.
George says.
Plant roots don't get
enough oxygen in clay
soils. Raised beds,
compost and other
amendments help.
Expanded shale is
another solution.
"Test plants had larger,
healthier root systems
with expanded shale,"
Mr. George says.
How do you know if you
need expanded shale? "In
summer, if the soil gets
big cracks when dry, you
definitely need expanded
shale," he says.
Here are the steps for
applying expanded shale:
•Till in 3 inches of
expanded shale, 6 to 8
inches deep.
•Till in 3 inches of
compost. Make sure the
compost is "finished" –
no green material.
•Mix the expanded shale,
compost and soil
thoroughly.
•Cover with a 3-inch
layer of mulch.
If you till expanded
shale and compost into
clay soil, then mulch,
you should never need to
add commercial
fertilizer, Mr. George
says. "As fully finished
mulch breaks down, it
acts as a slow-release
fertilizer."
You won't need to add
compost again, Mr.
George says. The mulch
will gradually break
down and work its way
into the soil. A year
after preparing the bed,
lay enough mulch on top
to bring the mulch layer
up to 3 inches. In
subsequent years, the
mulch breaks down
faster, and you will add
mulch in spring and fall
to bring the mulch depth
to 3 inches. Nothing
else – neither compost
nor commercial
fertilizer – is
necessary.
