WHAT IS HYDROPONICS?
Hydroponics comes from the Greek words hydro - water and ponos - labour and is a method of growing plants using mineral nutrient solutions in water, without using soil. Plants can be grown with their roots in the nutrient solution only or in an inert growing medium, such as mapito, coco substrate or clay pebbles.
Features of an
Ebb and Flow
system are plant pots filled with sterile grow medium which are inundated with
nutrient-rich water for a few minutes every hour. Most often, the pots sit in an
upper reservoir that drains into a lower reservoir. The commonly used grow
medium for Ebb and Flow gardens are rockwool, perlite, and vermiculite.
Drip systems
like the Wilma pictured, use an irrigation approach
that relies on drip emitters suspended just above the root zone. Growers can use
the emitters to regulate the amount of moisture reaching root media, along with
how the moisture is spatially distributed. These systems can be fine-tuned in
conjunction with temperature and humidity to create a near-continuous feed
cycle.
With
Nutrient Film Technique (NFT) plants
are placed in narrow grow channels and a “film” of nutrients is contained in
water in the bottom of the channel where roots are dangling. With this method an
abundance of oxygen is drawn in through the top of the roots and through the
irrigation solution as it passes by the lower parts of roots. NFT is a high
maintenance but an extremely productive method of hydroponics growing.
The easiest type of hydroponics garden to set up is a passive system in which plants sit in their pots that allow their roots to hang in a weak reservoir of nutrients. There are no moving parts, pumps or other complications, but there is often a problem with low amounts of oxygenation in the reservoir and this can slow plant growth. This is the least flexible of the systems mentioned because it is virtually impossible to make precise adjustments to feed rate and concentration, leading to production of smaller yields when compared with the other methods.
Aeroponics is very
high-tech and efficient method of growing. This type of garden is somewhat
similar to the NFT method. Plants are put in trays or pots that are filled with
a dense water-holding substance like rockwool or coco coir. Water which is
nutrition-rich, is supplied to the root zone media, which holds plants firmly in
place while retaining nutrients for uptake by roots. The aeroponics method
bathes plant roots in an aerosol spray of nutrition and water. Roots hang in the
spray area and the plants are supported by mesh pots. This system provides a
huge amount of oxygen to roots relinquishing the need for lots of root space,
because the delivery of nutrients is very efficient.