Maximum Yield Australia/New Zealand January/February 2020 | Page 51

These tests are carried out by
agricultural testing laboratories
that must meet certain standards for
accuracy to ensure reliable results. The
first step in obtaining any hydroponic
analysis is to contact an agricultural
lab and check their requirements
for sending samples. Some labs will
provide sampling kits including bottles
for water/nutrients and bags for foliar
samples to help prevent contamination,
however, many just provide
instructions on sample size, containers,
packaging, and delivery methods to
ensure the sample reaches the lab
in good condition. Once analysed,
the lab will provide a report for each
sample — basic reports may only
contain the levels of variables tested,
however, some labs may provide an
interpretation or guidelines to optimal
levels for the crop being grown.
Getting a lab water analysis test is a sensible
step to help avoid potential growth issues.
W
If you’re a hydroponic
grower, getting your
water, foliar minerals, and
nutrient solutions tested
and analysed by a lab is
something all cultivators
should do to ensure ultimate
crop health and production.
by Dr. Lynette Morgan
hile we know hydroponics can
provide advanced and balanced
plant nutrition, sometimes a little
reassurance or detective work is
required when it comes to the analytical
side of growing. Using laboratory testing
of water, nutrient solutions, foliage,
and growing mediums are all useful
tools for both small and large growers
alike and in these modern times are
becoming standard practice in many
indoor systems. Laboratory
testing is not as technical as it
seems; a small sample is collected
and sent away with the results
usually returned within a few days.
What can be confusing, however,
is the interpretation and use of this
valuable data to better optimise growth
and plant performance or to simply
identify a nutritional issue. Lab testing
can not only help with diagnosis of
plant problems, but assist with basic
adjustments to nutritional programs,
determine the suitability of a water
supply for hydroponic production, or
ensure food safety guidelines are being
met with microbiological testing.
Water Testing
Unless reverse osmosis (RO) or
distilled water is being used for a
hydroponic system, a water supply
analysis is always a good idea. Even
growers who consider their water
supply to be of high quality often find
surprises in their water analysis, many
of which can usually be corrected
or adjusted for. Most water supplies,
particularly those based on well water
or municipal supplies, do have some
minerals present and it is always an
advantage to know other parameters
such as the pH, EC, and alkalinity.
“
THE BASIC LAB TESTS
used by hydroponic
growers are water,
nutrient solutions, and
foliar mineral levels.”
Types of Lab Tests
The basic lab tests used by hydroponic
growers are water, nutrient solutions,
and foliar mineral levels. There
are less common tests such as sap
testing, analysis of growing substrates
(widely used in the nursery industry for
container mixes), and microbiological
testing for the presence of food safety
pathogens such as E.coli, which
applies more to commercial growers.
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