Hydroponics - a quick overview

Truly a wonder of modern science - hydroponic gardens produce bountiful harvests of fruit, vegetables, grains, herbs and flowers in places never before able to sustain growth. Hydroponic gardens produce the healthiest crops with the highest yields and vitamin content thanks to their perfectly balanced nutrient solutions. Modern hydroponic methods provide food for millions of people worldwide and supply you, me and the food service industry with superior produce. In fact, hydroponic cultivation is so effective, NASA has devised an advanced method of hydroponics for use in outer space. The science of hydroponics began with experimentation into deter-mining the elementary composition of plants. These experiments have been dated as early as 1600 A.D., however, records show that plants have been cultivated in soil free mixtures of sand and gravel even earlier. The hanging gardens of Babylon and the floating gardens of the Mexican Aztecs are perfect examples of early hydroponic gardening. Egyptian hieroglyphics have even been found depicting the cultivation of plants in water as far back as several hundred years BC.

The word "Hydroponics" was coined by Dr. W.F. Gerick in 1936 to describe the cultivation of both edible and ornamental plants in a solution of water and dissolved nutrients. The simple meaning is derived from the Greek "Hydro"- meaning water, and "Pones"- meaning labor. In this method of cultivation, plants are provided with the nutrients required for growth by a “nutrient” solution which is basically nutrient enriched mineral water. This nutrient solution can be circulated around the roots by  either the passive force of gravity or the active force of an electromechanical pump. Some systems simply bath the roots in nutrient solution and use an air pump to oxygenate the solution from below to prevent stagnation and provide the roots with important oxygen.

Plants grown hydroponically are healthier than their soil grown counterparts since they receive a perfectly balanced diet and do not come in contact with soilborne pests and diseases. Super efficient hydroponic systems like the ones we show you how to build conserve water and nutrients by preventing evaporation and runoff. Arid regions where water is scarce can now grow crops with hydroponics. Since hydroponic systems deliver water and nutrients directly to the plant, crops can be grown closer together without starving each other and healthier plants add to a higher yield. By growing crops in a sterile environment, under ideal conditions, hydroponics saves the costs of soil preparation, insecticides, fungicides and losses due to drought and ground flooding.

In soil, plants waste a tremendous amount of energy developing a large root system to search for moisture and nutrients. When grown hydroponically, the roots are bathed or sprayed with nutrients dissolved in water. This way their energy can be redirected into the production of more foliage, flowers, fruits and vegetables.
Plants grown hydroponically are healthier because they receive a well balanced 'diet'. They are more vigorous because little energy is wasted searching for water and nutrients. As a result, hydroponically grown produce is generally larger, tastier, and more nutritious than the same produce grown in soil. In order to give the physical support soil would normally provide, a sterile medium such as sand, gravel, rocks, cocofiber or rockwool (or combination of each) may be used. In the case of aeroponics, no medium is used and the plants receive physical support from baskets and in this case, wires suspended from the roof. These plants are rotated through a chamber that supplies their roots with a fine spray of water and hydroponic nutrients.

Oxygen to the roots increases a plant’s metabolism substantially. Some advantages of replacing soil with a sterile medium are:
1. Elimination of soil borne pests, funguses and diseases.
2. Elimination of troublesome weeds and stray seedlings.
3. Reduction of health risks and labor costs associated with pest management and soil care. 
At the Environmental Research Laboratory (ERL) at the University of Arizona in Tucson, Dr. Carl Hodges and Dr. Merle Jensen in conjunction with Walt Disney Productions, have developed new concepts for presenting hydroponic technologies to the public in an entertaining way. The ERL helped create two attractions called "Listen to The Land" and "Tomorrow’s Harvest" - both major facilities at Epcot Center near Orlando, Florida. Hydroponics is NASA's solution to provide a self sufficient food source for future space stations and proposed visitors to mars. The administration has sponsored a research program titled Controlled Ecological Life Support System (CELSS) in order to further develop the technology and carry it into the future. The picture below is of Epcot/ NASA’s Space Agriculture expo as seen from a tour of the Epcot Center attraction. The lighting used in these examples is high pressure sodium or HPS, which delivers an excellent spectrum of color and output in lumens. High Intensity Discharge (H.I.D.) lighting, which includes the HPS and metal halide type lamps, is the best lighting to use when gardening indoors or supplementing natural lighting outdoors due to its efficiency and close representation of the sun’s natural light color and intensity.