Print

4 Primary Growing Methods

m5In a soil garden, plants are rooted in the soil and draw nutrients from it. In hydroponics, a nutrient rich solution is fed directly to the plant roots. In some hydroponic growing systems an inert growing medium, such as perlite, vermiculite, expanded clay pebbles or pumice stones are used in place of soil. These growing mediums are porous and absorb the nutrient solution, allowing the plants to use it as needed.

In other hydroponic systems, like the NFT system, no growing medium is used and the plant roots are suspended in a grow channel.

The four most common methods of hydroponic gardening include:
  • Ebb and Flow
  • Drip Method
  • Nutrient Film Technique (NFT)
  • Passive System  

Ebb and Flow

The Ebb and Flow (also know as flood and drain) method of hydroponic gardening simply allows all the plants in the garden to be fed the same amount of nutrient solution at the same time. The growing bed is flooded and drained to a timed cycle, controlled by a simple on-off timer, providing fresh nutrients, water and oxygen to the plant roots.

Most Ebb and Flow systems, will flood the grow bed for 10 to 15 minutes of every hour, to every five hours, depending on the season and climate. (Just remember not too wet not too dry) In an Ebb and Flow system, the plant roots are most commonly grown in a medium of perlite, expanded clay pebbles or pumice stones.

An Ebb and Flow system, popular with many home hydroponic gardeners, is ideal for growing a wide variety of crops, since both long and short term crops do well in this system.

Drip

In a Drip system, the nutrient solution is delivered to the plants through drip emitters, on a timed system. The timed cycle flushes the growing medium, providing the plants with fresh nutrients, water and oxygen, as the emitter is dripping.

As with the ebb and flow technique, the emitters are usually scheduled to run for approximately 5-10 minutes of every hour or two.  In a drip system, the plant roots are most commonly grown in a medium of perlite, grow stones or vermiculite. The drip system is often used in commercial hydroponic facilities that grow long-term crops like tomatoes, cucumbers and peppers.

NFT

With the Nutrient Film Technique (also known as NFT), the plants are grown in channels, which the nutrient solution is pumped through. The plant roots are flooded by the nutrient solution as it passes by. Ideally, the bottom of the roots are exposed to the nutrient solution, while the top of the roots are exposed to air. Most NFT systems are fed on a very frequent timed cycle. For instance, 10 minutes of nutrient solution flow, followed by 5 minutes of nutrient solution drain. Since the plant roots are not in a growing medium, it is crucial that they are flushed often to keep them moist.

NFT is ideal for lettuces, leafy crops and herbs, all of which are short-term crops. Larger NFT channels can be used for long-term crops, as long as some form of plant support is provided.

Passive

The advantage of a Passive hydroponic garden is its low maintenance. A Passive system does not use pumps or timers to flood the root zone. The roots usually dangle in the nutrient solution and draw what they need from it.

A Passive system is generally slower growing and not as intensive as the other systems discussed.

Because there is no water movement, passive systems will often have low oxygen levels.