Maximum Yield Cannabis Canada 2017 July/August | Page 34

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plant analysis
MAKING SENSE OF
PLANT
ANALYSIS
by Dr. Lynette Morgan
From helping solve nutrient issues to
performing a vital role in crop research,
Dr. Lynette Morgan gives us the lowdown on
the benefits and drawbacks of plant analysis.
P
lant analysis has long been an integral part of
commercial greenhouse nutritional programs, but it’s
also a potential tool for smaller growers. Whether it’s to help
diagnose mysterious foliar symptoms or simply reassure
that all is well with nutrition, mineral analysis of the foliage
can provide useful and often insightful information on the
nutritional status of a plant or crop. However, it does have
limitations and some drawbacks that need to be understood
before the data is put to good use.
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The Process
Plant or foliar analysis involves taking a small sample
of leaves—usually the youngest recently expanded
leaf—from a number of plants and sending them off to
an agricultural lab for mineral analysis. Plant analy-
sis labs usually provide information or a kit contain-
ing sample bags and details of how to complete the
sampling process. This includes the number of leaves
required and whether these should be washed, refrig-
erated, or otherwise treated before sending them in.
If plants are particularly dusty or have been sprayed
with any chemicals or other products that may interfere
with the results, then washing the sample with reverse
osmosis or distilled water, followed by complete drying,
is advisable. Leaf samples can deteriorate quickly and
so should be sent off to the lab immediately.