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Hydroponics Reference Guide - Ideas and Information

Hydroponics Reference Guide


Hydroponics is the art of growing plants without the use of soil. There are hydroponic gardens all around the world. Suitable for small gardens and perfect for those with limited space, hydroponics is a system that can be easily set up.


Hydroponics is one of the fastest growing areas of gardening today as more people take up the hobby and commercial industries turn towards this efficient means of growing a wide variety of plants. What follows is a Hydroponic Reference Guide that features all the basic terminology you need to know in order to get started in this field.



What is Hydroponics?

Basically, hydroponics is growing plants without using soil. The nutrients are provided in a water-based solution to grow a wide variety of plants. Hydroponics is a technique that has been in use for over a century, but it was not until 1929 that it started to expand beyond research centers and into commercial and home use.

The advantage of hydroponics is that plants can be placed closer together which increases the yield per space being used. Plus, a wide variety of crops can all be grown close together using the same set of nutrients. There are no weeds or pests in a hydroponics garden, however, it does generally cost more for the equipment and it takes a little more training compared to standard soil gardening technique.

While the emphasis is on feeding the plants through a nutrient solution, the plants themselves are held upright through wires or other supporting systems.

The Different Types of Hydroponic Growing

What follows are the six basic types of hydroponic growing systems. Each of these systems has their advantages and disadvantages.


This form of hydroponic growing can be performed with either high or low pressure. The pumps break down the nutrients into smaller particles which make it easier for the plants to absorb. The pumps are connected to a timer which alternates the spray of the nutrients. Plants can grow very well under this system, but frequent cleanings and maintenance are needed. Plus, a power outage or timer malfunction can ruin your plants. 

Deep Water Culture:

This is perhaps the most popular of the hydroponic growing systems, probably because it is easy to set up and very inexpensive. All you need is air stones to add oxygen to the water which covers the roots of the plants. There is very little maintenance to the system as well, although controlling the PPM & pH balance is somewhat more difficult than other systems.


The drip system is the most common in the hydroponics world. The operation is very simple as the nutrients are dripped onto each plant. Many come with recovery systems to reuse the nutrients that were not absorbed. The popularity of this system is very simple as it is easy to use. Nutrient strength can easily be adjusted and you can grow a wide variety of plants. However, a single power outage and your plants are in trouble.

Ebb & Flow:

This is where the plants are alternatively flooded and then drained over a period of time. This system is controlled by a timer. It is fairly inexpensive and easy to maintain. However, if the power goes out during the draining process, you may lose your plants.

Nutrient Film Technique:

These systems have a constant flow of nutrients over the roots so you don’t need a timer. The plant itself is supported in a small plastic basket as the roots receive the nutrient flow on a consistent basis. This system is easy to set up and maintain, but a power outage will lose you your plants fairly quickly.


This is perhaps the simplest of all hydroponic systems. There are no moving parts as the nutrients are absorbed in the reservoir from the wick itself. You can build such as system as well with little difficulty. Plus, the wick system can be used to grow a wide variety of plants and support different growing mediums as well. However, a large amount of water is needed to run the system properly. Although power outages are something are of no concern.

Where Hydroponic Systems Can Be Placed

Each of the systems mentioned can be put in a number of different places, though indoors is generally the best as it protects the plants from the elements. There are a number of considerations to make when placing a hydroponic system as it will need adequate amounts of the following;

  1. Light
  2. Pest Control
  3. Temperature Control
  4. Ventilation

You can place the hydroponic garden outdoors if you can protect the plants from the elements and pests which can easily damage them. One of the main advantages of hydroponics is that the garden can be placed in almost any unused portion of your residence such as the narrow sides of houses, inside sheds or garages, along walls, and even spare rooms in the home. However, in some cases additional light and environmental control may be needed.

The Medium of Hydroponic Systems

While the water mixture supplies the nutrients to the plants, there is still a need for a type of solid media to support the root and plant structure. Generally speaking, most of the media that is used are inert materials that do not affect the nutrient solution, but provide adequate support for the plants themselves. However, there are certain types of media that do provide minerals or other materials that fortify the plants. What follows are the most common types of media that are used in hydroponics.

Brick Shards:

Similar to gravel, but has the disadvantage of altering the pH balance of the nutrient solution and will require an extra amount of cleaning before they can be used.


Also known as coco peat, this is the leftover material from the outer part of a coconut shell. This makes coir a complete natural grow and flowering medium for use in hydroponics.


This is a natural sedimentary rock that contains a high amount of silica, which is an essential mineral for growing plants.

Expanded Clay:

These are baked clay pellets that are inert, pH neutral and have no nutrient value on their own. Plus, clay pellets are inexpensive and can be re-used after being cleaned.


Commonly used in aquariums, gravel comes in different sizes, is very inexpensive and easy to clean and maintain. However, gravel is also very heavy and without a continuous water supply the roots of the plants will dry out.


This volcanic rock is a lightweight material that is basically expanded glass pebbles. It has a wide variety of uses and can be contained in plastic or set out loose. However, they can float away in ebb & flow systems.

Rock Wool:

This is perhaps the most common material used in hydroponic systems. Rock Wool is inert and allows for free drainage, making them perfect for systems that re-circulate the nutrients.


Sand has the advantage of being very cheap and plentiful. However as an inert material it does not drain very well at all.


Similar to perlite, vermiculite is a lightweight material in pebble form that can actually draw water and nutrients in a passive hydroponics system.

Polystyrene Packing Peanuts:

This is the same filler material you see used when mailing packages. They are very cheap, available and have great drainage. However, they are also very lightweight which many make them unsuitable for certain types of hydroponic gardens. What must be avoided are the biodegradable packing materials that can pass along styrene into the plants and to those that eat them which can create a health risk, so stick to polystyrene packing peanuts only.

The Types of Nutrient Solutions of Hydroponics

Essentially, the nutrients are dissolved into water solutions that consist of inorganic and ionic forms or materials. The most commonly found nutrients are as follows;

  1. Calcium
  2. Magnesium
  3. Potassium

The major nutrient anions that are found in the solutions generally consist of nitrate, phosphate and sulfate as well.

There are a number of different mixtures of nutrient solutions used in hydroponics. Each of these solutions is broken down in to either macro or micro nutrient mixtures.

Macronutrients consist of the following;

  1. Calcium Nitrate
  2. Magnesium Sulfate
  3. Potassium Nitrate
  4. Potassium Sulfate

Micronutrient mixtures are as follows;

  1. Boron
  2. Chlorine
  3. Copper
  4. Iron
  5. Manganese
  6. Nickel

The plants themselves will change up the composition of nutrient solutions as well, depleting some on a more rapid basis than others depending on their needs. In turn, this can alter the pH balance of the mixture. In this instance, concentrations of salt must be monitored along with the nutrient supply and balance of pH in order to maintain good growth and health of the plants.

Basic Hydroponic Terminology

What follows are a few basic terms in hydroponics that you may hear when purchasing equipment. Understanding these terms will help you in getting what you need for your hydroponic garden.

Automatic System:

This is where nutrient solutions are applied under water pressure in an automatic fashion. There is usually an irrigation system, such as pumps, that are used to supply the nutrients.

Closed System:

This is where the waste products are not allowed to escape. In essence, the system is completely closed off from the outside.

Manual System:

This is where the nutrients are applied manually, usually by hand, gravity or capillary means. This requires the adding of nutrients on a regular basis, but the actual distribution is done by a means that does not require pumps or electricity.

Nutrient Solution:

This is the mixture of nutrients and water which provides the plants what they need to survive. The nutrient solution is balanced for the needs of the plants as well.

Open System:

This is where the waste products are drained away from the system. Also called “run to waste”, this is the opposite of a closed system.

Solid Media:

This is the inert material where the roots of the plant will grow.

There are a number of solid media sources such as the following;

  1. Ceramic Chips
  2. Perlite
  3. Rock Wool
  4. Sand
  5. Scoria and more

This is the basic hydroponics reference guide. If you should have additional questions about hydroponics, it is best to consult the professionals who understand this form of gardening the best.