Hydroponic plants are exposed to light to allow for the process of photosynthesis, and plant roots are exposed to air allowing the roots to capture oxygen that they need to grow.
Nutrients mixed into water include:
• Phosphorus
• Nitrogen
• Calcium
In some hydroponic systems, a growing medium is used to support the plant roots and allow for more effective water absorption to the root structure. One type of growing medium commonly used is coconut coir — a shredded fibrous product made from coconut husk. A subset of hydroponics, called aeroponics, requires only light, water and nutrients, and does not use a growing medium.
BENEFITS OF HYDROPONICS :
• Enhanced plant yields: Hydroponic plants produce a greater yield of fruits and vegetables because in a hydroponic system plants are more densely spaced together compared to the size of land that would be needed to grow the same number of plants. Also, in a hydroponic system many of the elements that can enhance plant growth — such as the pH level of the water, nutrient content of the water, amount and type of light, etc. — can be better controlled.
• Less water: Hydroponic systems use less water — as much as 10 times less water — than traditional field crop watering methods because water in a hydroponic system is captured and reused, rather than allowed to run off and drain to the environment.
• Locally grown: Indoor hydroponic systems allow plants to grow almost anywhere all year round.
• Less space: Hydroponic systems come in a variety of designs including vertical stacking systems that take up a small amount of space.
There are several types of hydroponic systems.
WICK SYSTEM:
Plant roots grow down through a medium while an absorbent “wick” draws nutrient-filled water up from a water reservoir to the root system zone. The growing medium allows for air (oxygen) to reach the roots.
AIR-GAP SYSTEM:
Plant roots hang partially in nutrient-filled water while the upper part of the root system is exposed to air (oxygen).
RAFT SYSTEM:
Plants are positioned on a floating surface with their roots hanging in nutrient-filled water. An aquarium-type pump supplies oxygen to the water which is picked up by the roots.
EBB AND FLOW SYSTEM:
Plant roots grow through a medium. Nutrient-filled water is pumped on a frequent basis (e.g., every 30 minutes) to the root zone area and allowed to drain back into a water reservoir.
TOP FEEDER SYSTEM:
Plant roots grow through a medium. The growing medium allows for air (oxygen) to reach the roots. Nutrient-filled water is pumped to the top of the medium, allowed to percolate down to the root zone, and then drained back to a water reservoir.
Nutrient Film Technique (NFT):
Plants are positioned on a floating surface hanging in a trough that is slightly tilted. The plant roots hang with the upper part of the root system exposed to air (oxygen). The bottom part of the roots is exposed to nutrient-filled water that is pumped into the trough at the upper (higher) end. The water flows past (down) the other root systems and back into a water reservoir.
AEROPONICS:
Plant roots are positioned in an enclosed space and exposed to air (oxygen) where on a frequent basis (e.g., every 30 minutes) nutrient-filled water flows through the enclosed space or is sprayed via a mist.