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The word hydroponics is used to
describe a method of growing plants in water with added nutrients. Plants grown in soil use the water they are given
to dissolve the mineral nutrients in the soil which are then
taken up by the roots. If the nutrients are already in the water
then the soil becomes redundant.
Plants vary as to which species
thrive more using a hydroponic method but most will generally do
well. Hydroponics is used at a very young age by children
growing cress in 'egg heads', this method is done by simply
sprinkling cress seeds over a wet piece of cotton wool, no soil
is needed.
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Hydroponics
with leafy vegetables |
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Hydroponics are usually divided into
two types, medium culture and solution culture. Medium culture
uses a solid matter for the root system and is called by the
type of medium used ie gravel culture and sand culture etc.
These mediums are either top irrigation or sub irrigation.
Solution culture uses just nutrients and no solid matter, there
are three solution cultures, static, continuous flow and
aeroponics. Hydroponic containers can be made of almost any
material but are more commonly plastic, they must prevent light
from getting in as this will cause algae to appear in the
nutrient solution.
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NASA
plant physiologist Ray Wheeler checks onions being grown using hydroponic techniques. |
Top Irrigation
To
work using the top irrigation method you must apply your
nutrient solution to the medium surface. The solution can either
be done using drip feeding equipment that will administer timed
and measured doses regularly or it can be done by hand once a
day in large amounts, usually in sand.
Passive Sub Irrigation
This
method allows the water and nutrients to pass to the roots from
the bottom of the medium using capillary action. The medium used
should have big air pockets that will pass oxygen to the roots.
To work using this method situate your container in a shallow
layer of the nutrient solution or on a capillary mat that has
been soaked in it. Choose perlite, clay granules or gravel as
your medium. Refill the nutrient supply occasionally and check
pH balances are approx 6-6.5 to ensure sufficient nutrients are
being taken in.
Flood and Drain (Ebb and Flow)
Sub Irrigation
For this
method you will need a tray that is higher than your container
that is filled with the nutrient solution. Fill the tray with
your medium, best to use clay granules, and plant. Use a timer
that will make a pump fill up the tray with the nutrients, after
which the solution will run back down into the container.
Deep Water Culture
To
use this method you must hang your plants in a container so that
their roots are submerged in a solution of oxygenated and
nutrient filled water. Plants can be displayed in containers
with their roots threaded through netting or mesh and the heads
sitting on top.
Static Solution Culture
A
very easy method to do even for beginners. Called thus because
the nutrient mixture is static, the water is still and simply
bathes the roots. Use a container that is ideally dark plastic
but jam jars can be used on a smaller scale. Your container
needs a lid which if id does not come with one you can fashion
out of cardboard ensuring that it fits tightly on the top and is
secured with tape. If using jars or non dark plastic for your
container wrap it in foil to prevent algae growth. Cut out holes
in the lid through which you can put your plant(s). Try to keep
you plants in the centre of the lid. Add water and your nutrient
mixture, try to match up the mixture as to what your plants
need. Research what pH level is best for growth of the species
you have planted and test the mixture regularly to ensure they
are getting the right balance. Extra nutrients or water may need
to be added as the plants grow. Once you have put you dissolved
nutrients into the container top it up with water. If the
container is aerated the solution can be put in up over the
roots, if it is unaerated then you must allow a little gap
between the water and the roots for oxygen.
Continuous Flow Solution Culture
Continuous
flow does exactly what the name states, it is a method used to
send a continuous flow of nutrients around the roots of the
plants. Usually done on a larger scale using troughs or
hydroponic equipment designed for the job. Gathering information
about the nutrient content is simple as it can be collected from
the main tank, the solution is then distributed evenly
throughout the plants. Equipment failure and power cuts can
hinder the growth of plants.
Aeroponics
Similar
to the static solution in that the roots are kept in a dark
container but instead of being dangled in static solution the
roots are misted with the nutrients. When using the aeroponic
technique it may be necessary to purchase misting equipment.
Aquaculture
Ltd - Hydroponics systems, growth boosting nutrients.
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