Supplemental LED Lighting Increases Winter Tomato Production in Central North Carolina Greenhouse

Supplemental LED Lighting Increases Winter Tomato Production in Central North Carolina Greenhouse

Poster Session presented at American Society for Horticultural Science Annual Conference, 2015, in New Orleans, Louisiana

We tested winter tomato production in a central North Carolina commercial greenhouse (34.5 ̊ latitude) to compare between non-lit and LED-lit bays. 2,100 plants were grown hydroponically in a 7,400 sq ft greenhouse divided into three bays: a non-lit bay; a center guard bay; and a LED-lit bay. Plants were illuminated with 42 lights for a density of 1 light/ 59 sq ft for 15 hours/day.

Seeds were planted mid-October 2014. After 8 weeks of propagation under sole-source LED lighting, seedings were transplanted to the greenhouse. Bias was given to the non- lit and guard bays by placing the “strongest seedlings” in these bays 4 days before placing the lesser seedlings in the LED-lit bay. However, by 3 weeks under LED-light, the initially-lesser seedlings were more vigorous than the non-lit plants as indicated by more compact growth and greater stem diameter.

The first harvest of the LED-lit bay was 9 days earlier than the non-lit control. At final harvest, the LED-bay had a yield increase of 30%. Final evaluation indicated the LED-lit vines were taller and heavier with greater stem diameter. This study confirmed that lighting in a geographic region where greenhouse lighting was not traditionally used improved time to harvest and yield.

Authors

James Byrtus, LumiGrow Inc., Emeryville, California, USA
Dr. Melanie Yelton, LumiGrow Inc., Emeryville, California, USA

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