Tag: Pak choi

Update on trialing supplemental lights in Hawaii

By David Kuack

On Dec. 14, 2014, a Hort Americas blog update was posted about University of Hawaii graduate student Robert Saito, who is
comparing the growth of pak choi (Chinese cabbage) under T5 fluorescent lamps
and Philips GreenPower LED Production Module Deep Red/Blue 120 fixtures. Saito
has conducted seven trials. The first four trials were preliminary to determine
the best growing medium and which plants should be used to measure light effect
differences. Initially Saito was planning to grow mizuna, but he ran into
issues with micronutrient deficiencies and switched to pak choi instead. Both
of these leafy greens are in the Brassica family.

University of Hawaii graduate student Robert Saito is studying
the differences in growth of pak choi under fluorescent (top)
and LED lights (bottom).
Photos courtesy of Robert Saito


Preliminary results
Saito has measured fresh weight, height and chlorophyll
content of the plants grown under the two light sources.
“I also took SPAD readings to measure the relative chlorophyll
and there were differences among the treatments,” Saito said. “I am now going
to run the data statistically to see if there was a significant difference.”
Plant samples are also being analyzed for nutrient
content to see what kind of nutritional value they can offer to consumers.
“I am doing a tissue analysis to measure some of the
secondary metabolites,” he said. “I am looking at total phenolics, carotenoids
and glucosinolates. A mineral nutrient analyses will measure such things as
total nitrogen, phosphorus and potassium. Once the mineral and tissue analyses
are done then I hope to publish the results.”
For more:
Robert Saito, University of Hawaii, College of Tropical Agriculture and Human
Resources, Manoa, Hawaii; rjnsaiot@hawaii.edu.
David Kuack is a freelance technical writer in Fort Worth, Texas; dkuack@gmail.com. 
Visit our corporate website at https://hortamericas.com

Trialing supplemental lights in Hawaii

Although most people wouldn’t think that supplemental
lights would be needed to grow plants on the Hawaiian Islands, they may be able
to provide growers with a consistent, quality light source. University of
Hawaii graduate student Robert Saito is comparing the growth of pak choi
(Chinese cabbage) under T5 fluorescent lamps and Philips GreenPower LED
Production Module Deep Red/Blue 120 fixtures.

University of Hawaii research is comparing the growth of pak
choi (Chinese cabbage) under fluorescent lamps and LED lights.

“Some parts of Hawaii don’t have high light levels,”
Saito said. “There is also Kilauea volcano on the Big Island that’s been increasingly active since 2008. It
is spewing all kinds of emissions into the air, which can impact the quality of
plants grown outdoors. Field growers may be able to benefit from growing their
plants using supplemental lights in greenhouses or other indoor growing facilities.”

Saito is conducting three production trials growing pak
choi in an OMRI-certified peat-based growing medium.

Most people probably think Hawaii receives plenty of sunlight
for outdoor crop production. University of Hawaii graduate
student Robert Saito is trying to determine if indoor vegetable
growers could benefit from using supplemental lights.      

“The entire experiment is being done indoors,” Saito
said. “The plants are on a 14-hour photoperiod. The focus of my experiments is
on the benefits of using supplemental lighting. I have been looking at what are
the differences and similarities of growing pak choi under fluorescent lamps
and LEDs.”
For more:
Robert Saito, University of Hawaii, College of Tropical Agriculture and Human
Resources, Manoa, Hawaii; rjnsaito@hawaii.edu.

Visit our corporate website at https://hortamericas.com