Maximum Yield Modern Growing | Canadian Edition | May June 2017

feature
nutrient name application systems
DESIGN AND LAYOUT
Layout also affects the distribution of
nutrient solution to individual plants
around a drip irrigation system. Drip
systems may consist of either inline or
microtube systems. Inline systems are
more suited to large media beds where
the emitters are directly attached to
or embedded in the irrigation supply
pipe, which runs down the centre of the
bed. Microtube systems use tubing of a
smaller diameter, which is installed into
the lateral irrigation lines with emitters
or drippers fixed on the end. Each plant
or growing container can have one or
two microtubes with emitters pegged
into the substrate near the base of plant.
Using microtubes allows a more uniform
pressure at the emitters, provided the
irrigation is correctly designed and has a
pump of sufficient capacity.
One of the main issues encountered
by hydroponic growers is the differences
in volume of nutrient solution
received by plants in various parts
of the drip system. Some plants may
end up overwatered while others are
constantly too dry, and these issues
become difficult to remedy once
the irrigation system is in place. To
achieve uniform and constant nutrient
flow rates to all emitters in the
system, a ring or loop layout can be
installed. This consists of emitters
placed into lateral irrigation pipes
connected at both ends to a ring main
system, evening out the flow and
pressure round an irrigation system.
Each ring main is supplied by a main
irrigation pipe running directly from
a pump or pressure water supply.
This largely prevents the issue of
plants furthest away from the pump
receiving the lowest volume of nutrient
solution at each irrigation.
Selecting the correct irrigation pipe
diameter is an aspect of hydroponic
system design that is often overlooked.
The type, number, and flow rate of the
irrigation emitters determine the size of
irrigation lateral pipe needed in terms
of flow rate and pressure required. As
such, if the flow of nutrient appears too
low from some emitters, it is often more
effective to increase the diameter of the
delivery pipes rather than invest in a
more powerful pump. A large capacity
pump will not compensate for irrigation
pipes that are too small to carry the
nutrient solution flow rate required.
Float or raft systems may seem like a simple way
to supply nutrient solution, but oxygenation, EC,
and pH still need careful control.
Growers setting up hydroponic systems
for the first time or renovating an established
indoor garden to improve nutrient
management and delivery need to take
solution flow and delivery into consideration.
Under- or overwatering of individual
plants, slow or insufficient flow rates
in NFT systems, and inaccurate dosing
can all be prevented with the correctly
designed irrigation system.
36 feature