Hydroponics...the Basics

Advantages

Since Hydroponics can be used in conjunction with artificial sunlight, the growing season may be extended to include the winter months. Also many vegetables yield more per square foot. and in a shorter time than with soil. Nutrients are re-circulated resulting in much less pollution.

HYDROPONICS LOVES THE ENVIRONMENT as there is no need for harmful pesticides and weed killers!

Anchorage (media)...

'Growing mediums' are used to anchor the roots and give support to the plant. Since all nutrition necessary to grow plants are supplied by the nutrient solution, mediums are used primarily for anchorage. The two most popular growing mediums in Hydroponics are 'Heydite' which are small pieces of shale rock that can be re-used indefinitely making it environmentally-friendly. 'Rockwool' is also made of rock but has been melted, spun like cotton candy and molded into growing blocks and slabs. Smaller amounts of rockwool are used to support the plant and it may be added to compost after use.

Nutrient (plant food)

The plant food in a hydroponic garden is supplied to the plants by dissolving natural fertilizer 'salts' in water to make a 'nutrient solution'. It is important to feed the plants the proper amounts of each nutrient. Use a commercially prepared Hydroponic Nutrient, such as Oxygen

Oxygen is an important nutrient used by the plants' roots. In fact without ample oxygen to the roots the plant will drown. Hydroponics is very generous to plant root systems allowing for easy exchange of oxygen and other vital gases.

pH (potential hydrogen)

The pH level refers to the 'Acid' or 'Alkaline' level of the nutrient solution. The pH scale ranges from 0 to 14 with anything below seven considered 'Acidic'. Most plants prefer a pH level of between 5.5 and 6.5. A pH level that is too high or too low can affect the plants ability to use the nutrients.

To check and adjust pH using indicator solution simply remove 2 ml of nutrient solution from the reservoir to the test tube and add a drop of indicator. Check the colour chart on the bottle to determine pH level. One would try to achieve a yellow test colour, green colour indicates that the pH level is too high and a red colour too low. Adjust down with a couple of drops of pH Down and adjust up with straight tap water.

Seed Starting/Stem Cuttings

Simply insert a seed into a prepared 1" rockwool cube, cover with perlite or a piece of the rockwool cube. To make a stem cutting, cut two nodes below a growing tip with a sharp knife, dip in a rooting hormone and place immediately in a prepared 1" rockwool cube. A standard two-part nursery tray with a humidity dome is a great environment for seedlings and cuttings. Supply sixteen to eighteen hours of light per day. They will be ready to transplant into their permanent home when roots show through the bottom of the cube. Remember, rockwool needs an air space underneath to allow free drainage. Remove the humidity dome daily to allow new air exchange.

Transplanting

It is very easy to take plants that are already growing in soil and transplant them into a hydroponic system. Gently rinse the plants roots of soil in cold water. Spread the roots around the bottom of the hydroponic pot and fill with growing media.

Crops

Crops produced in today's modern greenhouse ranges are many and varied. They can be loosely categorized as follows:

vegetables including tomatoes, cucumbers, fancy lettuces, bell peppers, cherry tomatoes and a host of minor ones such as radish, melon and strawberry cut flowers e.g. roses, mums, carnations potted flowers e.g. geraniums, azalea, poinsettia, tulip numerous bedding plants

Growing Media

Porous, well aerated substrate are used as anchorage for the plants root system and feeding area. Rockwool and Heydite are the most popular as they are most readily available, and easiest to use and transport. There are various other mediums which are not as widely used.

Growing Techniques

There are different ways to bring water to the plants.

Nutrient Film Technique, Drip-Irrigation or Micro-Irrigation, Aeroponics / Deep Water Culture, Flood & Drain, Home Hobbyist Systems, Passive Planters / Hydroculture.

Carbon Dioxide Enrichment

In an outdoor garden the CO2 level in the air is about 300 parts per million (ppm) Plants thrive when they are able to take in a higher level of CO2. Growers today monitor their greenhouse CO2 levels with special purpose control monitors which in turn operate CO2 burners or generators to replenish CO2 consumed by the plants.

HAF (Horizontal Air Flow)

Working with CO2 enrichment and indeed an important part of the greenhouse environment is horizontal air flow. Conceived in the late seventies following research involving finer aspects of greenhouse air circulation, horizontal air flow, or HAF as it is now referred to, is widely used.

Security

Commercial growers end up with very sizeable portions of their yearly turnover as work-in-process. The closer the crop gets to harvest, the higher the risk of catastrophic loss, should a key part of the greenhouse's climate control system fail. Accordingly, growers go to great lengths to protect themselves. Early warning is a vital part of their security. Most now employ automatic phone dialers with electronic voice simulation to alert them of impending problems long before serious crop damage can occur.

Biologicals

Environmental concerns are uppermost in the minds of today's consuming public. The horticultural industry has been working for many years to reduce its dependence on chemical pesticides, many of which have been linked to cancers. Numbers of key pesticides have been deregistered for particular crops, others have been removed from the market altogether. Promising advances have been made in the use of predator insects in greenhouse ranges as natural biological control against pest insects. While much work remains to be done to educate the grower in their use, progressive members of the industry are now well on their way to 100% biological insect control.

Bumble Bees

Until recently, pollination of greenhouse tomato crops was accomplished with a labourious method of fruit truss vibration utilizing battery operated hand-held vibrators ("electric bees") manually touched against mature flower sets. It was a strictly artificial way of simulating natural pollination in the absence of a natural outdoor environment where wind and insects are the vectors. In today's modern tomato ranges, hives of bumble bees are placed strategically amongst the crop and left to accomplish naturally what has been, until now a monotonous and tedious task for greenhouse staff.

Lighting

In order to get the best possible results from a Controlled Environment Agriculture System, we will need to bring the spectrum and intensity of sunlight indoors. This is accomplished using High Intensity Discharge lamps. These lamps, in conjunction with specially designed luminaries, will reflect light downwards to plants, where it may be utilized to the maximum.

Climate Controls

Modern greenhouses employ advanced environment control aids such as relays, humidistats, thermostats, CO2 injection systems and fans which are often controlled by a central computer. Smaller systems employ various individual control units.

Bioponics

The organic hydroponic display or Bioponics, we believe, is of significant interest to both commercial and hobby growers. This method employs an organic tea based nutrient solution with added microbial agents to facilitate their breakdown into mineral elements which plants are able to take in.

Courtesy of Homegrown Hydroponics