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Amending Clay Garden Soil

The foundation of successful gardening is good soil. I
always tell beginning gardeners that if they get the
soil right they are two-thirds of the way to a beautiful
garden. Unfortunately, few of us move into a home where
the soil is already perfect. When I began digging my
garden I was faced with a thick layer of highway grade
gravel that was left over from when the then vacant lot
was used as a community park. In order to remove all the
gravel it was necessary to take with it most of the
arable topsoil. That left me with a heavy, clay-based
subsoil that was harder than a terra cotta pot.

Few things can strike fear into the hearts of gardeners
like heavy clay soil. It is almost impossible to grow
anything in the stuff. It is gooey when it is wet, and
brick hard in the summer.

Why is Clay Soil So Troublesome?

The problem is that clay particles are very small in
comparison to others found in the soil. For instance,
if a clay particle were the size of a baseball, the
average grain of sand would be, relatively speaking,
the size of a Greyhound bus. Because clay particles
are so tiny they pack together easily and become very
dense, virtually impermeable to water and air, which
are essential for healthy soil.

Use Humus to Improve Clay Soil

Now if you have clay soil, there is no reason to call
in a backhoe or a D-9 dozer to dig it out. A better
idea is to simply amend it. This will help break up
the clay particles so water can trickle through and
delicate roots can grow in the air pockets. The best
way to separate these particles is to integrate coarser
or larger particles such as humus. Humus is any decayed
organic material like leaf mold, old ground up pine bark
or compost. If you do not have a compost bin you can
purchase bagged soil conditioner or even have it
delivered by the cubic yard.

Get to Digging

Begin by loosening the clay in the area where you want to
create a bed. Dig down about 12 inches. Once the ground is
broken up add 3 inches of bagged garden soil, 3 inches of
compost and 3 inches of ground, decomposed pine bark.

Once you have added all the amendments, till the ground until
everything is well-blended. If you do not have access to a
tiller you can do this by hand with a garden fork or
shovel. It just takes more effort.

You will know that you have the texture right if you can
squeeze a moist handful of soil in your fist and it easily
falls apart when you open your hand.

Add Manure to Your Soil

Now to further improve your soil, add some well-rotted
manure. Not only does it help the composition of the soil
but it brings nutrients as well. When you purchase a bag
of basic commercial fertilizer like 13-13-13 you get
13% nitrogen, 13% phosphorous and 13% potassium but
nothing else.

Granted these are staples that plants need, but they also
need other trace elements such iron, boron, and magnesium.
Manure has all these trace elements plus a heaping dose
of nitrogen, phosphorous and potassium. For plants,
manure is like a well-balanced meal and a multi-vitamin
all in one.

I recommend purchasing manure in bags from your local
garden center. Typically bagged manure has gone through
a heat process that sterilizes any weed seeds that might
be lurking in there and it helps to deodorize it. Also,
you do not have to worry about it being too fresh and
burning your plants. Check the back of the bag for
recommend rates of application.

Once you have the texture just right and have added the
manure, top the soil with 2 to 3 inches of wood mulch.
I prefer pine bark chips, but any wood mulch will do.
As the wood decomposes it will supply your garden with
plenty of organic matter plus reduce weeds and retain
moisture.

Good to Know:

Sandy soils can be amended too. Simply till in 2 to 3
inches of humus such as manure or compost to help bind
the soil. This will improve water retention as well
as add nutrients.