organic hydroponics
Since pH-lowering acids commonly used in hydroponics such as nitric and
phosphoric acids are not organic, pH is best left to stabilize on its own. Some
organic nutrient products naturally have a high pH, so growers should try to
select those that have a more suitable pH range for use in soilless systems.
Organic Nutrients
There are a few different approaches to obtaining and using organic nutrient
sources in a hydroponic system. It can be difficult to get a balanced and suitably
high ratio of all the essential minerals from organic sources alone, so experimentation with different products is helpful. There is a range of liquid organic
nutrient concentrates on the market, as well as some fertilizer salts that are considered organic and naturally occurring to help boost growth where required.
Generally, sulphate trace elements, such as iron sulphate, copper sulphate,
zinc sulphate, manganese sulphate and magnesium sulphate (Epsom salt), are
allowed under organic production, so these can be used to help round out any
deficiencies that may occur with organic nutrients. An organic iron chelate
can be made by mixing iron sulphate with citric acid powder to replace the
synthetic iron chelate (EDTA or DTPA) commonly used in traditional hydroponics to ensure ongoing iron availability. Growers often need to blend two
or more organic liquid fertilizers to provide sufficient and balanced nutrient
Some organic nutrient products
naturally have a high pH, so growers should try to
select those that have a more suitable pH range for
use in soilless systems.”
levels for most
hydroponic crops.
An organic base
product (often a
concentrated fish
emulsion base or
similar) blended
with an organic
liquid calcium is
a good place to
start. An organic
nitrogen product
may be required
Organic greenhouse tomatoes grown in a substrate of coir, perlite
later on. Growers
and vermicast with organic nutrients and additives.
should aim to use
products that have
been designed for soilless systems wherever possible.
The main difficulty with running organic systems is obtaining sufficient
amounts of nitrogen and calcium, which are required in large amounts
by plants. Organic systems rely on microbes in the root zone to convert
organic compounds into plant-available nitrogen sources and sometimes
this process does not occur fast enough for uptake. Calcium is difficult to
obtain rapidly from organic nutrients as it relies on the breaking down of
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Maximum Yield USA | January 2015