May 2024 - 16

TECHNOLOGY INNOVATIONS
natural light levels are still high in September, so paying a
high demand charge based on one dark day simply doesn't
make sense. Adjusting the output intensity in shoulder
months with relatively high natural light levels allows
growers to peak shave and reduce their utility bill.
Outside of the electrical bill, adjusting the output
intensity is critical to matching the light levels to the
crop's stage of development, with younger plants typically
requiring less light at first and then higher light levels as
they grow. We often see growers starting their lights at
50% intensity, then increasing gradually over the course
of one to two weeks to give the crop time to adapt to the
additional light.
DIMMING IN RESPONSE TO REAL-TIME
LIGHT LEVELS
With real-time dimming, the objective is to have a
uniform light level at the head of the crop. Otherwise, the
crop often experiences drastic changes in light intensity as
fixtures turn off either completely or in a stepwise manner.
Without real-time dimming, the light sensors in the
greenhouse would read a high value and shut off some
or all the fixtures at once. Alternatively, an increasingly
cloudy day would see the light levels jump up when
the natural light levels drop below a critical point.
Operationally, this means the fixtures are turning on
and off more frequently, which carries a certain strain
on the system.
Cropwise, the plants' photosynthetic apparatus
oscillates between unsaturated and oversaturated, which
can cause plant stress and damage. With real-time
dimming, it isn't about turning lights on and off but about
targeting the best light level at the head of the crop and
adjusting accordingly.
SPECTRAL TUNING FOR ADVANCED
MORPHOLOGY AND QUALITY CONTROL
More studies are showing light spectrum's importance
and specificity to the crop and varieties, ultimately leading
more growers to seek a system that allows them to adjust
the light spectrum according to the stage of development,
crop type, morphology and quality objectives.
With dynamic LED lighting, growers can program a
light recipe to apply far red light during certain times of
the day, to have end-of-day (EOD) treatments to impact
the crop's chemical profile, and to adjust the spectrum
completely in the event of a crop change. With every new
study pointing to the nuance of the light spectrum, it
is making less and less sense to install a system with a
fixed, narrowband spectrum.
Following the installation of a LED solution, Sollum
typically adds three to four preset light recipes to the
16
MAY 2024 GPNMAG.COM
Lighting systems
that growers
can easily
adjust based on
objectives, like
flowering, helps
manage timing.
grower's SUNaaS account to get growers started. With
regular production follow-ups, we also work with them
to finetune the recipes, add to the list and build their
dynamic LED playbook.
ZONING HOW YOU WANT, WHEN YOU WANT
Greenhouses typically have multiple varieties, if not
also multiple crops. If the lighting solution doesn't offer
multi-zoning capabilities, then none of the above criteria
matter as the " best case " lighting parameters will need to
be applied to the entire greenhouse.
By creating zones as a software layer, Sollum's SUNaaS
cloud platform enables growers to expand their view of
zones beyond breakers and electrical layouts. Creating
and modifying zones is as simple as dragging to select
the fixtures and create the zone, then naming the
new zone. Simple as that. Each zone can be adjusted
individually, with different light recipes, dimming
parameters and photoperiods per zone.
The greenhouse industry is constantly in flux, so
growers deserve a dynamic lighting system that can keep
up with these changes and be futureproof. A greenhouse
may grow tomatoes this year, strawberries next year
and cucumbers after that. Greenhouse systems need to
accommodate this flexibility.
Dynamic LED lighting brings unparalleled control
and efficiency to greenhouses, empowering growers to
optimize their operations for better yield, quality and
sustainability.
Rose Séguin is agronomist at Sollum Technologies and assists
its R&D team in identifying best practices for LED lighting in
greenhouses. She can be reached at r.seguin@sollum.tech.
http://www.GPNMAG.COM
May 2024

Table of Contents for the Digital Edition of May 2024
