container mixes), and microbiological
testing for the presence of food safety
pathogens such as E.coli, which applies
more to commercial growers. 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
analyzed, 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.
Water Testing
W
hile we know hydroponics can
Unless reverse osmosis (RO) or
provide advanced and balanced
distilled water is being used for a
plant nutrition, sometimes a little
hydroponic system, a water supply
reassurance or detective work is
analysis is always a good idea. Even
required when it comes to the analytical
growers who consider their water
side of growing. Using laboratory testing
supply to be of high quality often find
of water, nutrient solutions, foliage,
surprises in their water analysis, many
and growing mediums are all useful
of which can usually be corrected
tools for both small and large growers
or adjusted for. Most water supplies,
alike and in these modern times are
particularly those based on well water
becoming standard practice in many
or municipal supplies, do have some
indoor systems. Laboratory testing is
minerals present and it is always an
not as technical as it seems; a small
advantage to know other parameters
sample is collected and sent away with
such as the pH, EC, and alkalinity.
the results usually
returned within
a few days. What
THE BASIC LAB TESTS USED
can be confusing,
however, is the
by hydroponic growers are water, nutrient
interpretation and
solutions, and foliar mineral levels.”
use of this valuable
data to better
optimize growth
A basic water supply analysis
and plant performance or to simply
should test for: TDS (total dissolved
identify a nutritional issue. Lab testing
solids), EC, pH, alkalinity, nitrogen (N),
can not only help with diagnosis of
phosphorus (P), potassium (K), calcium
plant problems, but assist with basic
(Ca), sulphur (S), magnesium (Mg),
adjustments to nutritional programs,
sodium, chloride, iron, manganese,
determine the suitability of a water
zinc, boron, and copper, which are
supply for hydroponic production, or
of importance to hydroponic plant
ensure food safety guidelines are being
nutrition. While the presence of low
met with microbiological testing.
levels of macro elements such as N,
P, K, Ca, Mg, and S in a water supply
Types of Lab Tests
is not a concern, high levels of these
The basic lab tests used by hydroponic
will require adjustment of the nutrient
growers are water, nutrient solutions,
formulation to keep the solution in
and foliar mineral levels. There are
balance. In most water supplies Ca
less common tests such as sap testing,
and Mg are the most common elements
analysis of growing substrates (widely
found, while N, P, and K are much less
used in the nursery industry for
likely to be at plant-usable levels.
“
If you’re a hydroponic
grower, getting your
water, foliar minerals, and
nutrient solutions tested
and analyzed by a lab is
something all cultivators
should do to ensure ultimate
crop health and production.
by Dr. Lynette Morgan
Maximum Yield
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