searching for an optimum supplemental led intensity for ...€¦ · 1 university of guelph, guelph,...
TRANSCRIPT
©2017. LumiGrow, Inc. All right reserved.
(800) 514-0487 • [email protected] • www.lumigrow.com
D. Llewellyn1 K. Schiestel1 Y. Zheng1 M. Yelton2
1 University of Guelph, Guelph, Ontario, Canada, 2 LumiGrow Inc., Emeryville, California, USA
Searching for an Optimum Supplemental LED Intensity for Winter Production of Cut Gerbera at Northern Latitudes
Introduction Methodology
At higher latitudes, cut flower growers rely on supplemental lighting for maximizing production in the darker months.
Horticultural LEDs have been proven to produce similar or better crops (in terms of yield and quality) compared with HPS; while also having longer lifespans, higher energy efficiencies & can be controlled in terms of spectral distribution & intensity.This project sought to determine the opti-mum light level for cut gerbera production during the 2015-16 supplemental lighting season (ie. Nov. thru Feb.) at higher lati-tudes
• Specialized lighting research greenhouse facility University of Guelph, Ontario, Canada
• LumiGrow’s Pro 325 LED fixtures provided 5 dif-ferent crop-level intensities:
• 40, 75, 135, 170 & 180 µmol m-2 s-1
• 14 hr supplemental daylength provides 1.7 to 7.7 mol day-1 of supplemental PAR
• 4 concurrent replicate plots of each intensity
• Cut gerbera cultivar: Ultima
• 15 week trial
©2017. LumiGrow, Inc. All right reserved.
(800) 514-0487 • [email protected] • www.lumigrow.com
Metrics
Vegetative Phase
Growth and reproduction metrics:• Vegetative growth metrics (# of leaves,
stem length, chlorophyll content• Day to first flower formation and day to
harvest
Harvest metrics:• Fresh mass of each harvested flow-
er (including stem), flower diameter, stem length
Chlorophyll Content Index during vegetative phaseBi-weekly leaf counts during vegetative phase
Size & maturity of representative plants @ 12 weeks after transplanting for 40, 135 and 180 µmol m-2 s-1
supplemental light treatments
©2017. LumiGrow, Inc. All right reserved.
(800) 514-0487 • [email protected] • www.lumigrow.com
Generative Phase
Conclusions
Number of flowers initiated, per plant, by the end of the trial (15 weeks after transplanting)
Flower harvest metrics including:A- Number of days between flower initiation and harvestB- Mean flower diameterC- Mean stem fresh weightD- Mean stem length
• During Vegetative Growth Phase
• Chlorophyll content and the number of leaves increased with increasing supplemen-tal light levels
• Increasing trends diminished after 135 µmol m-2 s-1
• During Regenerative Phase
• Flower initiation and devel-opment is accelerated with increasing supplemental light levels
• Little difference in flower size, but more robust stems with higher supplemental light levels
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