Hydroponics 101

Hydroponics is a subset of hydro-culture and is a method of growing plants using mineral nutrient solutions, in water, without soil. Terrestrial plants may be grown with their roots in the mineral nutrient solution only or in an inert medium, such as perlite, gravel, bio char, mineral wool, expanded clay pebbles or coconut husk.

Researchers discovered in the 18th century that plants absorb essential mineral nutrients as inorganic ions in water. In natural conditions, soil acts as a mineral nutrient reservoir but the soil itself is not essential to plant growth. When the mineral nutrients in the soil dissolve in water, plant roots are able to absorb them. When the required mineral nutrients are introduced into a plant’s water supply artificially, soil is no longer required for the plant to thrive. Almost any terrestrial plant will grow with hydroponics. Hydroponics is also a standard technique in biology research and teaching.

Some of the reasons why hydroponics is being adapted around the world for food production are the following:

  • No soil is needed for hydroponics
  • The water stays in the system and can be reused – thus, a lower water requirement
  • It is possible to control the nutrition levels in their entirety – thus, lower nutrition requirements
  • No nutrition pollution is released into the environment because of the controlled system
  • Stable and high yields
  • Pests and diseases are easier to get rid of than in soil because of the container’s mobility
  • Ease of harvesting
  • No pesticide damage
  • Plants grow healthier
  • It is better for consumption

Today, hydroponics is an established branch of horticulture. Progress has been rapid, and results obtained in various countries have proved it to be thoroughly practical and to have very definite advantages over conventional methods of horticulture.

There are two chief merits of the soil-less cultivation of plants. First, hydroponics may potentially produce much higher crop yields. Also, hydroponics can be used in places where in-ground agriculture or gardening are not possible.

Six Common Types of Hydroponic Growing Systems

Aeroponic System:

  • One of the most high tech growing systems
  • The growing medium is primarily air
  • The roots hang in the air and are misted with nutrients every few minutes
  • A timer must be used to control the nutrient pump to ensure the plants are properly misted with the nutrients

Drip System

  • The most widely used type of hydroponic systems
  • A timer controls a submersed pump that releases a nutrient solution onto the base of each plant
  • In a Recovery Drip System, the excess nutrient solution is collected and reused
  • The Recovery Drip System is more sustainable, however the pH and nutrient strength levels may vary because the nutrient solution is reused
  • In a Non-Recovery Drip System, it does not collect the excess solution
  • The Non-Recovery Drip System must have a precise timer to ensure that the least amount of nutrient solution is wasted

Ebb and Flow System

  • This system works by temporarily flooding the grow tray with nutrient solution and then draining the solution back into the reservoir, which is controlled by a submersed pump on a timer
  • Several times a day, the timer comes on and allows the pump to release the nutrient solution into the grow tray
  • When the timer shuts off the nutrient solution is collected back into the reservoir
  • This system can be modified in many ways such as filling the grow tray with grow rocks or gravel
  • One main disadvantage of this system is the possibility of a power outage and/or pump timer failures, due to the growing medium that is used

N.F.T.: Nutrient Film Technique System

  • The most commonly thought of hydroponic system
  • N.F.T. systems have a constant flow of nutrients, therefore no timer is needed for the submersed pump
  • The nutrient solution is pumped into the grow tray over the plant roots and is then drained into the reservoir
  • The only grow medium that is used is air
  • The plants are typically supported in small plastic baskets, with the roots dangling into the nutrient solution
  • This system faces the possibility of power outages and pump failures

Water Culture Growing System

  • A very simple to use hydroponic system
  • A styrofoam platform typically holds the plants and floats on the nutrient soltuion
  • An air pump is used to supply air to a bubbling stone that releases the nutrient solution and supplies oxygen to the plant roots
  • Leaf lettuce is the predominant plant grown in this type of system, very few other plants grow well in the Water Culture System

Wick Growing System

  • The simplest of all hydroponic systems
  • The Wick System is a passing system, meaning it has no moving parts
  • The nutrient solution is released into the grow tray through a wick
  • There are several different growing mediums that can be used in this hydroponic system

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