Great Lakes Moment: It’s a UFO. No, the aurora borealis. No, it’s Leamington greenhouses!

Great Lakes Moment: It’s a UFO. No, the aurora borealis. No, it’s Leamington greenhouses!
January 4, 2021 John Hartig

Great Lakes Moment is a monthly column written by Great Lakes Now Contributor John Hartig. Publishing the author’s views and assertions does not represent endorsement by Great Lakes Now or Detroit Public Television.

If you gaze off to the east from Detroit, Grosse Pointe or Downriver, chances are you will see bright lights adrift in the night sky. Upon closer inspection, you might notice an extraordinary amount of light being emitted from the ground. At first, you might question whether it is a UFO or the aurora borealis.

However, the phenomenon is actually light pollution from nearly 3,000 acres of greenhouses in Leamington and Kingsville, Ontario – nearly 30 miles away. Some people living Downriver on the U.S. side have noted that they feel disoriented looking east in the evening and seeing a glow that looks like a sunset.

Essex County, Ontario, is the southernmost region of Canada with one of the longest growing seasons in the nation. Coupled with fertile soils, the region is well known for its agriculture. In fact, Leamington has long been considered the “Tomato Capital of Canada.” The county also has a reputation for its bell peppers, cucumbers, apples, strawberries, grapes and now cannabis. Chances are that you have eaten tomatoes, bell peppers and cucumbers from Leamington. Tilray, formerly Aphria, operates a 1.1 million square foot cannabis facility in Leamington, producing approximately 243,000 pounds of cannabis per year.

Growth and expansion of greenhouses has increased dramatically in Leamington and Kingsville over the past few decades. Greenhouses allow farmers to grow year-round, control climatic conditions, optimize yield and make harvesting easier. Growing higher quality vegetables and greater varieties, and increasing harvest rates and efficiencies, leads to a higher profit margin for growers.

Leamington now has the largest concentration of commercial greenhouses in North America, giving it the new moniker of “Greenhouse Capital of North America.”

Regarding the growth and expansion of greenhouses in Leamington and Kingsville, Joseph Sbrocchi, general manager of the Ontario Greenhouse Vegetable Growers, notes that “the numbers and the size of the growth has been unprecedented.”

In January 2020, Leamington had 2,890 acres of greenhouses and an additional 120 acres under construction. Hundreds of new greenhouses are projected to be built in Leamington and Kingsville over the next few years. For comparison, those 2,890 acres of greenhouses in Leamington – with its population of about 28,000 – are enough to fill Little Caesars Arena in Detroit, where the Detroit Red Wings and Detroit Pistons play, 155 times.

However, the unintended consequence of this massive scale of greenhouses is light pollution, so much of it that there is considerable public outcry over the nightly greenhouse glow with residents advocating to bring back the night sky. In fact, residents on both sides of the border are now clamoring to bring back the starry skies.

Ecosystem Impacts

For billions of years, life on Earth has relied on a predictable rhythm of day and night. Plants and animals depend on Earth’s daily cycle of light and dark rhythm to govern life-sustaining behaviors such as reproduction, nourishment, sleep and protection from predators.

The International Dark-Sky Association encourages communities, parks like Point Pelee National Park in Leamington – the first Canadian national park designated as a dark preserve in 2006 – and protected areas around the world to preserve and protect dark sites through responsible lighting policies and public education.

Some of their concerns of light pollution on ecosystems include:

  • light pollution radically alters the nighttime environment of nocturnal animals by turning night into day;
  • artificial lights impact wetlands that are home to amphibians such as frogs and toads, whose nighttime croaking is part of the breeding ritual – this interferes with reproduction and reduces populations;
  • light pollution can disrupt predator-prey dynamics because prey species use darkness as cover from predators; and
  • artificial light can cause birds that migrate or hunt at night to wander off course and collide with lighted buildings and towers, and can cause birds to migrate too early or too late and miss ideal climate conditions for nesting, foraging and other essential behaviors.

Response to Light Pollution

In October 2020, Kingsville’s city council passed a bylaw prohibiting greenhouse odor and light pollution. Kingsville is now considering a bylaw amendment on where new greenhouses can be located at its Jan. 27 meeting.

In December 2020, Leamington’s city council passed a new Greenhouse Light Abatement Bylaw, requiring greenhouse operators to keep sidewalls and end walls completely covered with curtains from one hour before sunset to one hour after sunrise. Curtains must also be completely closed on greenhouse ceilings from one hour before sunset until one hour after sunrise, except between the hours of 2 a.m. and 6 a.m. During that time, the ceiling curtains must be at least 90% closed.

Ontario Greenhouse Vegetable Growers is a nonprofit organization that represents approximately 200 farmers responsible for over 3,200 acres of vegetables in Ontario with farmgate sales of $950 million in 2018, and that support over 13,000 jobs – a contribution of $1.8 billion to the economy.

OGVG recognizes the legitimate community concerns with greenhouse nighttime glow. At the same time OGVG is concerned that the recently enacted bylaws may prove to be both impractical and unenforceable. OGVG has engaged the Ontario Ministry of Agriculture, Food and Rural Affairs, the University of Windsor, the University of Guelph, and Agriculture and Agri-Food Canada to identify lighting strategies and abatement techniques and technologies that can work in the unique climate of southern Ontario.

So, the next time you are out and looking east over the Detroit River or Lake St. Clair, look for the nightly greenhouse glow. Should they allow such light pollution and take away starry nights? Should there be a moratorium on greenhouse expansion until full environmental impacts and costs are measured and mitigating strategies and technologies explored?

John Hartig is a board member at the Detroit Riverfront Conservancy. He serves as the Great Lakes Science-Policy Advisor for the International Association for Great Lakes Research and has written numerous books and publications on the environment and the Great Lakes. Hartig also helped create the Detroit River International Wildlife Refuge, where he worked as the refuge manager until his retirement.

Read more Great Lakes Moments on Great Lakes Now:

Great Lakes Moment: A new vision for the former McLouth Steel site in Trenton

Great Lakes Moment: Sacred land of the Wyandot of Anderdon Nation

Great Lakes Moment: Detroit River and western Lake Erie get a checkup

Great Lakes Moment: Cleanup of contaminated river sediment begins at old Uniroyal site

Roller Coaster: Michigan’s long history with environmental contamination

Featured image: The moon shining over Sugar Island on the lower Detroit River with greenhouse lights approximately 30 miles east in Leamington, Ontario. (Photo Credit: John Hartig)


  1. George Mite 3 years ago

    Living in the middle of this pollution is life-altering. Leamington & Kingsville councils need to enforce – much as Ohio has. (Slight correction – not 3,000 greenhouses but 3,000 acres covered)

    • John H Hartig 3 years ago

      Thanks. What has Point Pelee NP said about this, considering they are a dark skies park?

  2. Starr Livingstone 3 years ago

    Point Pelee National Park is a Dark Sky Preserve. RASC Windsor was instrumental in this DSP designation. IDA had nothing to do with it.
    Starr Livingstone
    Royal Astronomical Society of Canada – Windsor Centre

    • John H Hartig 3 years ago

      Grassroots organizations are trying to get a dark skies designation for Belle Isle in Detroit.

  3. James Proffitt 3 years ago

    The lights are a frequent topic of conversation, usually in the form of a question like “What is that?” from people in the Port Clinton area….

    • John H Hartig 3 years ago

      Same in Michigan

  4. Jack 3 years ago

    Even here in Madison, Ohio, 80 miles/130km from Leamington, you can see the lights coming from these greenhouses. Very disturbing and upsetting.

    • John H Hartig 3 years ago

      Some people in MI have noted they are somewhat disoriented seeing what appears to be a sunset in the east

  5. Paul Raitano 1 year ago

    Can a low emissivity or silvered film be placed on the inside of the greenhouse glass? These will help keep heat in and reduce the light going out. This I’ve heard is less expensive than curtains and they don’t require moving.

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