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Greenhouses and Light Pollution

Greenhouses and Light Pollution

Supplemental electric lighting for greenhouses may be essential for extending the growing season in northern climates, but it comes with a not-so-hidden cost: environmental light pollution. The consequences of this pollution may range from irate neighbours in rural...

Light Transmittance through Greenhouse Glazing

Light Transmittance through Greenhouse Glazing

Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published: 18/10/01. Look at a greenhouse manufacturer’s product specifications and you will see that the light transmittance of single-pane clear glass is typically 88 to 91 percent. Compared...

Far-Red Lighting and the Phytochromes

Far-Red Lighting and the Phytochromes

Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published 18/06/04. Most LED grow lights feature blue and red LEDs whose peak wavelengths – approximately 450 nm for blue and 660 nm for red ­– have been chosen to coincide with the spectral...

Phytochrome and PSS

Phytochrome and PSS

Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd.   Published: 2016/12/09 Horticultural lighting is currently one of the fastest-expanding markets in commercial lighting, with projected revenues of several billion dollars in less than a...

Photometry and Photosynthesis

Photometry and Photosynthesis

Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd.   Published: 2014/12/10 UPDATE 15/04/13 -- This article was first published on December 10, 2014. A revised version was published as "LED Lighting for Horticulture" in the Mar/Apr 2015...

Horticultural Lighting Metrics

Horticultural Lighting Metrics

Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd.    Published: 08/04/2017  UPDATE 17/08/26 - This article was first published on August 25th, 2017 in Urban Ag News. It was all so easy until recently. Plants require light in...

Botanical Light Pollution

Botanical Light Pollution

Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published: 2016/02/17 Blue-rich light from LED streetlights, we are told, is the nemesis of professional and amateur astronomers. Blue light is preferentially scattered by the atmosphere,...