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Aeroponics, Drip Method, Ebb and Flow, NFT (Nutrient Film Technique), Aeration MethodAeroponics
The plants are grown in containers or nets which allow the roots to dangle in air above the nutrient solution. An aeroponics mister pump forces a spray of nutrients through the roots at very frequent intervals. For example, one minute of spray followed by 4 minutes of drainage. The act of spraying ensures that additional oxygen is mixed with the nutrient solution providing an enriched oxygen, nutrient solution that is very beneficial to the plant and results in rapid growth.Plants achieve an increase in water and nutrient uptake over conventional soil gardening methods. Soil tends to bind crucial minerals and therefore plants tend to expend a lot of energy pulling the minerals away from the positive ions such as clay in the soil.
This method also eliminates the potential of water logging the root system or exposing the root system to a depleted oxygen supply resulting from constantly recirculating the nutrient solution without using an air pump to replenish the oxygen supply in the water.
The aeroponic cloning systems are also good for starting new cloned plants.
Drip Method
In a Drip system, the nutrient solution is delivered to the plants through drip emitters on a timed system usually scheduled to run for approximately 5-10 minutes of every hour. The timed cycle flushes the growing medium, providing the plants with fresh nutrients, water and oxygen as the emitter is dripping.The plant roots are most commonly grown in a medium of perlite, grow rocks or rockwool. This system is often used to grow long term crops like tomatoes, cucumbers and peppers.
Ebb and Flow: (also known as flood and drain)
The Ebb and Flow method periodically floods the plant growth medium and roots with water and nutrient solution and then allows the water to drain off exposing the growth medium and roots to air. This procedure can be compared to high tide and low tide at an ocean beach. At high tide the beach sand is flooded with seawater. Then at low tide the water drains back into the ocean exposing the sand to the air. The sand remains moist for a period of time and then becomes flooded again at high tide.In Hydroponics, the flow pattern of water and nutrient solution must be timed so that the growth medium remains moist during the Ebb period and does not allow the plant roots to dry out before the next flow of water. The growth medium used varies in moisture holding ability which must be taken into consideration when setting the timing cycle.
Most Ebb and Flow systems will flood the grow bed for 10 or 15 minutes of every hour or two. In an Ebb and Flow system, the plant roots are most commonly grown in a medium of perlite, rockwool or expanded clay pebbles. During the Flow period the plant roots and growth medium are flooded with water and nutrient solutions. Then during the Ebb period the roots are exposed to air enabling them to acquire the necessary oxygen. The growth medium retains moisture for a considerable period of time, ensuring that the plant roots do not dry out between the scheduled nutrient solution flows.
Nutrient Film Technique (NFT)
In the Nutrient Film Technique, the plants are normally contained in plastic pots with slitted bottoms that permit the roots to dangle through to the water and nutrient solution in the channel below. The bottom of the root system dangles in the water while the upper part of the roots remain in air at all times ensuring that the roots have access to the necessary oxygen.The only purpose of using a growth medium would be to hold the plant roots in place or to enable the seed or seedling to sprout.
