Have you ever looked at the soil in your garden and
considered it as anything more than soil? If not you should
because there is a lot more there than meets the eye. It
performs many functions that you may not be aware of and having
good quality soil in your garden is essential for your plants.
In this article we will look at the functions of soil, what
different types there are and finally some ways to make it
Functions of Soil
The most immediately
apparent function of soil is a medium to support plant life. It
provides support both physically and biologically. Physical
support is provided by allowing the plant to grow its roots
through the soil to hold itself in place. Biological support is
provided by its ability to hold nutrients and water that the
plant needs. It also supports other types of life as well.
Microorganisms and insects live in the soil and they in turn aid
plant life by helping to decay organic material and adding
structure to the soil. Soil allows the growth of food crops
which are consumed by humans and also plants used in the
creation of medicines. Microorganisms like fungi and bacteria
that live in soil and are used to produce antibiotics. All life
on earth is dependant on it either directly and indirectly. This
includes the plant life in your garden.
What is Soil Made
The four major components of soil are mineral matter,
organic matter (humus), water and air. Mineral matter refers to
the inorganic elements in the soil e.g. stones, gravel and makes
up to 40%-60% of its volume. This part of the soil usually
originates from the bedrock that lies beneath the soil. Organic
matter (humus) is the decayed remains and waste products of
plants and animals and has a great effect on the chemical
properties of the soil e.g. availability of nutrients. Almost
40%-60% of a soil's volume can be space and this is occupied by
water and air.
Different Types of Soil Texture
Soil texture is defined as the size distribution of different
mineral particles. These mineral particles are at their most
basic level the following: sand, silt and clay. Sand particles
are 2 to 0.05 mm diameter, silt particles are 0.05 to 0.002 mm
diameter and clay particles are less than 0.002 mm diameter.
Combination of these particles exhibit different properties in
soil and some combinations favour plant life better than others.
The following are the most common classes of soil texture:
Contains a high percentage of clay particles and
feels lumpy to the touch. The small size of the clay particles
means that they clump together quite readily and there is less
room for air spaces. Consequently clay soils have poor drainage
and do not hold nutrients very well. This is a heavy soil and is
sticky when wet making it hard to work with. As much as possible
you should take steps to improve the drainage of this type of
soil. You will learn how later on in this article.
Contains a high percentage of silt particles and feels
smooth to the touch. This soil is a well drained soil due to the
size of the particles allowing space for water to permeate. This
soil holds nutrients more readily than clay soil due to the
spaces. It is easy to cultivate but can be compacted quite
Contains a high percentage of sand
particles and feels gritty to the touch, Allows for quite a lot
of space in between particles and as a result is very free
draining. This has its disadvantages however as it does not hold
water and essential nutrients can get washed away.
This is the best type of soil texture you can have in
your garden. This is soil whose properties are controlled
equally by the percentages of clay, silt and sand particles. It
is well drained but does not loose water too easily as is the
case with sandy and sometimes silty soils. The fact that it
retains water means it also retains nutrients for your plants to
use. It has a great structure and is easy to cultivate.
What Makes a Soil Healthy?
Healthy soil must be fertile and
have a good structure.
For a soil to be fertile it must
have nutrients readily available and a pH value at a recommended
level for the plants that will reside in it. Nutrients that
should be available are the essential nutrients nitrogen (leaf
growth), phosphorous (root growth) and phosphorous (overall
health). As well as the essential nutrients there should also be
trace elements like calcium and magnesium. The pH level of the
soil refers to its acidity or alkalinity and each plant has its
own preferred value range. Plants placed into fertile soil will
grow up to be very strong and healthy specimens (that is if
other conditions like light levels and climate are favourable as
The other determiner of a healthy soil is its
texture. We learned about different types of soil texture
earlier in this article. Soil having a loamy texture is the
healthiest and it should be strived for if at all possible. In
general a soil that retain nutrients and allow water and air to
permeate it will be beneficial for the life of your plants.
How to Create Healthy Soil
No matter what type of soil you
have the addition of organic matter will work wonders for its
health. Organic matter is plant and animal residues in varying
forms of decomposition. It will replenish the nutrients in your
soil and improve its texture. You may have heard countless times
about adding your leftovers and glass clippings to a compost
heap. This is a great idea as your compost is the best form of
organic matter. Compost in an advanced stage of decomposition
(dark and without smell) is magic for your soil. It encourages
microorganism activity causing soil particles to clump together
and form aggregates. The aggregates allows for spaces in the
soil therefore increasing its drainage. This is especially
beneficial for clay soils, which have poor drainage. Other forms
of organic matter are animal manure and peat moss.
your soil is lacking in nutrients and you don't have access to a
compost heap you have a choice of using inorganic or organic
fertilizers. Inorganic fertilizers (inorganic salts,
manufactured chemically) can be purchased at your local garden
and are applied in a dry form that is raked lightly at the base
of a plant or in a liquid form. While inorganic fertilizers will
work fine they have a number of disadvantages: they release
their nutrients too quickly and there is some evidence to show
that plants develop a resistance to inorganic fertilizer methods
over time, requiring more and more to achieve the same effect.
Organic fertilizers are more in tune with nature because they
are created from the remains or by-product of an organism. They
act slower but they 'amend' the soil rather than the quick
'feeding' it like inorganic fertilizers.
The pH of your
soil will also affect its fertility. Each plant has its own
preferred pH value range. To learn more pH and how to change it
read my Soil pH article here http://www.gardenstew.com/blog/e3-9-soil-ph-and-its-effect-on-your-garden.html
Soil like a lot of things in the garden requires
maintenance. We have learned about the different types of soil
texture, what constitutes a fertile, healthy soil and how to
create it if it does not exist. The next step is to step out
into your garden, take a look at your soil and help your plants
out if your soil is of a poor quality. Your plants will thank
you ten-fold believe me. Good luck!
About the Author:
Francis Kilkelly runs a great gardening community at
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