Discovered in the 1800's
Plant physiology researchers discovered in the 1800s that plants
absorb essential mineral nutrients as inorganic ions in water.
In natural conditions, soil acts as a mineral nutrient reservoir for
the plant, but the soil itself is not essential for plant growth.
When the mineral nutrients in the soil are dissolved in water,
plant roots can still absorb them. When the required mineral
nutrients are introduced into a plant's water supply artificially,
believe it or not, soil is no longer required for the plant to
survive. Almost any plant can be grown this way, but some will do
better than others.
A Soil-Less System
Coming from the Greek words ‘hydro’ for water, and ‘ponics’ for
labor, the word hydroponics in gardening terms specifies a
type of gardening where the plants don't have their roots in soil. This soil-free type of gardening depends entirely
on a water based system that is enriched with nutrients.
These nutrients can be in the form of specially formulated
chemicals for hydroponics gardening, or they can consist of a variety
of natural nutritional ingredients found in nature. The use
of either nutrient form is solely dependent upon the gardener.
Since hydroponics gardening is a soil free system, using containers
is the easiest method for growing plants. When using a container,
it is filled with a growing medium that is suitable for the plant.
This medium is how the water and nutrients are transferred to the
root system. Hydroponics can also be done without a container.
With a little bit of research you can find out much more about
growing media. Here's a quick overview of the most popular
- Shale - A simple and easy solution
for the first time gardener.
- Diahydro - A natural
sedimentary rock medium. It consists of the fossilised
shells of algae.
- Expanded Clay - Also known as 'hydroton' or 'leca'
, trademarked names (light expanded clay aggregate)
- Rockwool - Made from basalt
rock. Pprobably the most widely used medium in Hydroponics.
When this medium is dry, be very careful so you don't inhale any
particles. Doing so may carry a health risk.
- Coco Coir - A compressed
medium created from the husks of coconuts.
- Perlite - A volcanic rock
that has been superheated into very lightweight expanded glass
pebbles. Has similar properties to vermiculite but
generally holds more air and less water.
- Vermiculite - Like perlite.
It has been
superheated to expand into light pebbles. Vermiculite
holds more water than perlite.
- Sand - Cheap and easily
available. However, it's heavy, holds moisture, and can clog
roots and must be sterilized between uses.
- Gravel - Aquarium gravel is
excellent, although any small gravel will work provided
it's washed. Gravel is inexpensive, easy to keep clean,
drains well and won't become waterlogged. It's also heavy.
If your system doesn't provide continuous water, the roots may
- Polystyrene Packing Peanuts - Yep,
regular packing peanuts, although you don't want the bio-degradable
There are two main types of hydroponics:
They are Solution Culture Systems and
Medium Culture Systems. Solution
culture does not use a solid medium for the roots, just the nutrient
I'll briefly list the more well know hydroponic gardening systems
below. Each one is an entire topic in itself and you should
plan on doing further research if you'd like to use one of these
- Static solution culture
Plants are grown in containers of nutrient solution such
as glass Mason jars, plastic buckets, tubs or tanks. The
solution is usually aerated but if un-aerated, the solution
level is kept low enough so enough of the roots are above the
solution so they get adequate oxygen. A homemade system
can be aerated with an aquarium pump
- Continuous flow solution culture
The nutrient solution constantly flows past the roots of many
plants. Works better for automation than "Static Solution
Culture" because adjustments to pH and nutrient concentrations
can be made in one large storage tank that serves many plants
rather than in many individual containers.
The roots of a plant are suspended in a darkened chamber and
periodically covered with a mist or fog of nutrient solution.
No solid medium is used. Aeroponics is a good method for
plants with thick roots such as trees. Thick roots may not get
adequate aeration in static or flowing systems.
- Passive sub-irrigation
The medium generally has large air spaces to allow oxygen
to the roots. Capillary action brings water and nutrients
to the roots from the base of the medium.
- Flood and Drain (or Ebb and Flow)
There is a plant tray above a reservoir of nutrient
solution. At regular intervals, a timer causes a pump to
fill the upper tray with nutrient solution, after which the
solution drains back down into the reservoir.
- Top irrigation
Nutrient solution is periodically applied to the medium
surface. Usually, it is automated with a pump, timer and
drip irrigation tubing.
- Ultrasonic Fogging
Feeding plants by atomizing water droplets. Producing a thick
cloud of fog around the base of the plants root structure.
- Deep Water Culture
Suspending the plant roots in a solution of nutrient rich,
oxygenated water. Usually contained in a bucket.
Before you decide to dive into hydroponics. let me give you a few
advantages and disadvantages to consider:
- No soil is required.
- Soil borne diseases are virtually eliminated.
- Weeds are eliminated.
- Generally fewer pesticides are required (because of the above two reasons).
- Edible crops are not contaminated with soil.
- Water use can be substantially less than with irrigation of
outdoor soil-grown plants.
- Hydroponics Gardening is often the best plant production method in areas
where soil is not available, such as on an apartment balcony.
- Usually requires a greater technical knowledge than
growing plants in soil (Geoponics).
- Usually requires extra equipment.
- Usually requires more frequent maintenance than geoponics.
- If timers or electric pumps fail or the system clogs or gets
a leak, plants can die very quickly.
- Hydroponics Gardening can make it more expensive to grow
plants than with soil-based methods.
- "Solution culture hydroponics" requires that the plants be supported
since the root system has no support without a solid medium.
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