In water culture hydroponics, either deep water
or nutrient film technique, there is no percola-
tion. The liquid nutrient does not pour through
the grow medium but rather is run across and
through the root systems of the plants involved.
Because of this, nutrients are not rinsed
out on a continual basis. Instead, they
are recirculated. Nutrients are
only removed when the
system is drained
and cleaned.
The temperature and
absence of light in the water,
as well as the general cleanliness
of the tank, feed lines, and pump, will
have major impacts on just how long a system
can go between rinsing and cleaning. Typically,
between one and three weeks seems to work best. If
growers change the water more often than necessary,
their workload and nutrient costs go up. If they change
it too seldom, the likelihood of increased harmful
microorganisms and plugged up system components
can go up. Finding the balance is important for every
grower. Healthy plants require good nutrition and they
are much more likely to put off the chemicals from
plant allelopathy, which fight off competition from
other parasitical plant life forms.
With soil systems, the intent is to create healthy
and plentiful living and beneficial microbes to assist
the root system’s uptake of nutrients. However, much
of the organic food that builds healthy microbe
populations will also support many
undesired bacteria and fungi. As
such, many water culture growers
prefer to use ionic nutrients. These
are the nutrient salts that beneficial
microbes create when they react with
organic non-ionic nutrients. This lack
of a food source will aid in keeping
harmful microbe populations from
developing. On the other side, fungi-
like mycorrhizae, which are still very
beneficial for deep water culture
crops, will also not have any support
to develop and grow.
If growers decide to use organic
nutrients in a deep water system, it
is recommended they make routine
changes. Growers should also
clean the solution, keep light from
entering the water reservoirs and
channels, and keep the oxygen-
ation of the water at its maximum.
Though not generally considered
a plant nutrient, oxygen is a primary
nutrient required by the root system.
A lack of oxygen can aid in the
development of anaerobic bacteria,
which is undesirable.
“Another aspect that has a
major impact on the uptake
of many nutrients and needs
TO BE CAREFULLY
MONITORED IS PH.”
grow cycle
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