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Light Trespass an Emerging Issue in Some Greenhouse Production Areas

Thu, Mar 31st, 2022, created by Thomas Ford
Light trespass caused by the installation and use of LEDs and other lighting systems in greenhouse production facilities is the latest issue to arise in some communities across the USA and Canada. Many greenhouse operations did not think twice when it came to installing supplemental lighting for floriculture crops, hydroponic vegetables, or cannabis because of the inherent benefits that supplemental lighting will bring to their operation’s crops. 
When greenhouse lighting systems are first discussed in the lunchroom, growers and managers tend to focus on the benefits of supplemental lighting with nary a thought to the consequences that the installation of supplemental lighting may bring from the community that surrounds them. Growers operating in states with strong "right to farm” laws often feel insulated from litigation, but in many areas this state support seems to be waning.
Activists belonging to a variety of organizations are lobbying state and local leaders to enact ordinances which would require that all production lighting be contained within the greenhouse structure. Any light that leaks from the structure would be viewed as a light trespass violation which could subject the greenhouse operator to a variety of fines that can be levied by the local municipality that crafted these regulations or ordinances.
Activists lobbying against light trespass often cite that lighting at night interferes with human circadian rhythms and that night-time illumination can be linked to a variety of human medical issues ranging from obesity, depression, sleep disorders, to diabetes. Some activists also cite that nighttime illumination can disrupt world ecosystems. Research that these organizations cite indicates that night-time illumination by artificial light can lead to mating disruption in frogs and that some predators (mammals and birds) may not be able to locate prey successfully due to the illumination of the night sky. Navigational systems for birds and sea turtles are also reported by some researchers to be adversely impacted by nighttime illumination. 
Activists concerned with night sky illumination also cite that the views of stars, planets, and constellations are often obscured or blocked by the glow of lights from greenhouses and urban environments. Activists view night lighting as an encroachment of a basic human right (to view the night sky) and suggest that it can adversely impact what is described as night sky heritage opportunities for people in the community.
As a greenhouse operator you must be aware of this growing trend to restrict the amount of light escaping from illuminated greenhouses into neighboring communities. Most activists want regulations that require the installation and use of blackout curtains in greenhouses that can contain 98% of the light being produced by a greenhouse lighting system to the inside of the structure. For new greenhouses, the installation of blackout curtains is an added capital expense that when deployed correctly should minimize community complaints while maintaining your company’s compliance with new and/or existing light trespass ordinances. 
Older greenhouse ranges that have recently added LED and/or other lighting systems may find it difficult to retrofit their existing greenhouse ranges to accommodate blackout curtains. In some situations, it may be more cost effective for growers to design and build a new greenhouse production facility that incorporates blackout curtains in its design than to retrofit an aging obsolete greenhouse facility. At this juncture I am unaware of any grants or low interest loans at the federal or state level that can help to defray this added expenditure for business owners.
In conclusion, greenhouse operators like all farmers should remain politically active and be aware of proposed ordinances that may place new restrictions on your operation. By staying informed and being politically active you may be able work with community leaders to establish operational guidelines that preserve your ability to maintain your livelihood while safeguarding the rights of your neighbors. 

About the Author:

Thomas Ford

Commercial Horticulture Educator, Penn State Extension

Tom has worked for over 33 years with Cooperative Extension in Maryland, North Carolina, and Pennsylvania. During his career he has worked intensively with vegetable and fruit growers, greenhouse and nursery operators, landscape and turf professionals and area farmers with their production and pest management issues.


Tom is a native of Central Maryland and resides with his wife, Laura and their four sons in Duncansville, PA. Tom has a B.S. degree in Ornamental Horticulture from the University of Maryland and a MBA from Frostburg State University in Frostburg, MD. Tom currently serves as a Commercial Horticulture Educator with Penn State Extension and is housed in the Cambria County Extension Office in Ebensburg, PA.

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