Nutrient Film Technique (NFT)
The
nutrient film technique is most commonly used in commercial
hydroponic applications and is used to grow large quantities of leafy
vegetables that have small root systems. The water to feed the
plants is pumped through small narrow troughs. The NFT system
is generally not used in aquaponics.
Deep Water Culture (DWC)
The
deep water culture application is much like the NFT system except it
doesn’t use a thin film of water it uses a deeper bed of water
using a suspended float. Just like the NTF system there are
only a certain types of plants will thrive in a system where their
roots are continually submerged.
Media Filled Grow Beds
The
most commonly used growing method in aquaponics is media filled grow
beds. With this system the medium, otherwise known as
gravel or clay pellets, is used to suspend the plants. The media from the grow beds keeps the nutrients where the
roots are located. The gravel or clay also naturally recycles
the waste from the fish.
Another
benefit from using the media filled grow bed method is the fact that
you can grow more of a variety of plants and vegetables.
Actually, you can grow just about anything when you use media filled
grow beds than you can any of the other systems.The other two systems work best for leafy greens but have a harder
time with anything else.
You
will have to decide whether you want to use gravel or clay pellets.
Many people pick gravel because it costs less and is easier to get. However, they later come to realize that perhaps gravel was not the
best choice. Gravel is very heavy and you have to keep in mind
that you will have the weight of the gravel, as well as, the water
and both of these will have an effect on your structure. Gravel
could also affect the pH of your water. But this will depend on
the type of gravel you use.
Clay
pellets are a much better choice. Clay pellets are lighter than
gravel and won’t affect the pH of your system because the pellets
are pH neutral. Additionally, the pellets retain moisture but
will still allow air to get to the plants roots. This is what
makes the clay pellets the preferred product among most people who
maintain an aquaponic garden.
