Horticulture Archives - All Things Lighting® Association https://www.allthingslighting.org/category/academic-articles-and-research/horticulture/ Illuminating the Complicated! Fri, 01 May 2026 20:12:53 +0000 en-US hourly 1 https://www.allthingslighting.org/wp-content/uploads/2023/08/cropped-ATLA-favicon2-32x32.jpg Horticulture Archives - All Things Lighting® Association https://www.allthingslighting.org/category/academic-articles-and-research/horticulture/ 32 32 Intro to Horticultural Lighting https://www.allthingslighting.org/intro-to-horticultural-lighting/ https://www.allthingslighting.org/intro-to-horticultural-lighting/#respond Wed, 04 Feb 2026 17:40:12 +0000 https://www.allthingslighting.org/?p=5282 Introduction This article is based on a presentation I had the pleasure of delivering at the recent Canada Light Expo 2025 in Toronto. My aim with the presentation was to offer a brief overview of some key aspects of horticultural lighting and to highlight how it differs from architectural lighting. I was surprised by the […]

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]]> https://www.allthingslighting.org/intro-to-horticultural-lighting/feed/ 0 Lighting Uniformity in Horticulture https://www.allthingslighting.org/lighting-uniformity-in-horticulture/ https://www.allthingslighting.org/lighting-uniformity-in-horticulture/#respond Fri, 24 Jun 2022 03:34:28 +0000 https://www.allthingslighting.org/?p=2824 Written in 2015, “Greenhouse Design and Control” (Ponce et al. 2015) is extraordinarily comprehensive in its coverage of greenhouse design issues, from site selection through structural load bearing analysis and ventilation technologies to greenhouse automation using adaptive neural fuzzy inference systems. On the topic of greenhouse lighting, however, it has only this to say: “The light level in the greenhouse should be adequate and uniform for crop growth.”

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]]> https://www.allthingslighting.org/lighting-uniformity-in-horticulture/feed/ 0 Quantifying Light Pollution Sources https://www.allthingslighting.org/quantifying-light-pollution-sources/ https://www.allthingslighting.org/quantifying-light-pollution-sources/#respond Thu, 03 Feb 2022 08:02:02 +0000 https://www.allthingslighting.org/?p=2658 time light pollution is sadly familiar to all of us. While our grandparents and great-grandparents may talk fondly of seeing the Milky Way in their youth, with thousands of stars scattered across the dark summer sky, we are mostly content with seeing a few dozen stars through the never-ending dusk of urban and suburban skies.

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]]> https://www.allthingslighting.org/quantifying-light-pollution-sources/feed/ 0 Horticultural Lighting Design and Déjà Vu https://www.allthingslighting.org/horticultural-lighting-design-and-deja-vu/ https://www.allthingslighting.org/horticultural-lighting-design-and-deja-vu/#respond Mon, 13 Sep 2021 00:25:34 +0000 http://test.allthingslighting.org/?p=2316 The phrase déjà vu translates from French as “already seen,” which nicely describes a current issue with horticultural lighting design. The introduction of LED technology may have kick-started horticultural lighting as an innovative industry, but we have yet to learn an important lesson from four decades of architectural lighting. The Importance of Design Data Prior to the […]

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]]> https://www.allthingslighting.org/horticultural-lighting-design-and-deja-vu/feed/ 0 The Effect of Near-Infrared Radiation on Plants https://www.allthingslighting.org/the-effect-of-near-infrared-radiation-on-plants/ https://www.allthingslighting.org/the-effect-of-near-infrared-radiation-on-plants/#respond Mon, 19 Apr 2021 09:00:25 +0000 https://www.allthingslighting.org/?p=1945 Look at any textbook on botany and you will find this maxim: plants respond to optical radiation in the spectral range of 280 nm to 800 nm. Period, end of discussion. The question is, how was this spectral range (sometimes referred to as Photobiologically Active Radiation, or PBAR) determined? This question addresses issues beyond mere […]

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]]> https://www.allthingslighting.org/the-effect-of-near-infrared-radiation-on-plants/feed/ 0 Specifying LED Colors for Horticultural Lighting https://www.allthingslighting.org/specifying-led-colors-for-horticultural-lighting/ https://www.allthingslighting.org/specifying-led-colors-for-horticultural-lighting/#respond Fri, 29 Jan 2021 08:09:02 +0000 https://www.allthingslighting.org/?p=1914 This paper proposes an LED “color” specification that represents a given SPD using a small number of radial basis functions, to provide a metric for comparing biologically similar SPDs. It  further introduces a trainable fuzzy logic SPD classifier that can compare biologically similar SPDs for specific horticultural applications.

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]]> https://www.allthingslighting.org/specifying-led-colors-for-horticultural-lighting/feed/ 0 Defining Photosynthetic Photon Efficacy https://www.allthingslighting.org/defining-photosynthetic-photon-efficacy/ https://www.allthingslighting.org/defining-photosynthetic-photon-efficacy/#respond Fri, 26 Jun 2020 19:39:58 +0000 https://www.allthingslighting.org/?p=1859 There has been some discussion online and in presentations recently about the issue of photosynthetic photon flux. The argument goes as follows: Photosynthetically Active Radiation (PAR) is somewhat arbitrarily defined as optical radiation within the spectral range of 400 nm to 700 nm. Exposing plants to far-red radiation (defined as 700 nm to 800 nm) […]

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]]> https://www.allthingslighting.org/defining-photosynthetic-photon-efficacy/feed/ 0 Climate-based Annual Daylight Modelling for Greenhouses with Supplemental Electric Lighting https://www.allthingslighting.org/climate-based-annual-daylight-modelling-for-greenhouses-with-supplemental-electric-lighting/ https://www.allthingslighting.org/climate-based-annual-daylight-modelling-for-greenhouses-with-supplemental-electric-lighting/#respond Fri, 22 May 2020 17:26:52 +0000 https://www.allthingslighting.org/?p=1831 Recent advances in LED-based luminaire design have enabled greenhouse operators to temporally control both the photon flux density and spectral irradiance incident upon the plant canopy.

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]]> https://www.allthingslighting.org/climate-based-annual-daylight-modelling-for-greenhouses-with-supplemental-electric-lighting/feed/ 0 Greenhouses and Light Pollution https://www.allthingslighting.org/greenhouses-and-light-pollution/ https://www.allthingslighting.org/greenhouses-and-light-pollution/#respond Wed, 22 Apr 2020 22:09:52 +0000 https://www.allthingslighting.org/?p=1729 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 areas to municipal bylaws that may prohibit the use of supplemental lighting during certain hours of the […]

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]]> https://www.allthingslighting.org/greenhouses-and-light-pollution/feed/ 0 Light Transmittance through Greenhouse Glazing https://www.allthingslighting.org/light-transmittance-through-greenhouse-glazing/ https://www.allthingslighting.org/light-transmittance-through-greenhouse-glazing/#respond Thu, 14 Nov 2019 23:35:14 +0000 https://www.allthingslighting.org/?p=1250 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 to double-wall polycarbonate with a transmittance of 80 percent, it would seem that glass is the better […]

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]]> https://www.allthingslighting.org/light-transmittance-through-greenhouse-glazing/feed/ 0 Far-Red Lighting and the Phytochromes https://www.allthingslighting.org/far-red-lighting-and-the-phytochromes/ https://www.allthingslighting.org/far-red-lighting-and-the-phytochromes/#respond Thu, 14 Nov 2019 23:06:22 +0000 https://www.allthingslighting.org/?p=1241 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 absorption peaks of chlorophyll A and B molecules. In doing so, […]

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]]> https://www.allthingslighting.org/far-red-lighting-and-the-phytochromes/feed/ 0 Phytochrome and PSS https://www.allthingslighting.org/phytochrome-and-pss/ https://www.allthingslighting.org/phytochrome-and-pss/#respond Fri, 15 Feb 2019 22:26:20 +0000 https://www.allthingslighting.org/?p=272 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 decade. From the perspective of a professional lighting designer, the market opportunities are enticing. Whether it is lighting for […]

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]]> https://www.allthingslighting.org/phytochrome-and-pss/feed/ 0 Photometry and Photosynthesis https://www.allthingslighting.org/photometry-and-photosynthesis/ https://www.allthingslighting.org/photometry-and-photosynthesis/#respond Fri, 15 Feb 2019 22:22:39 +0000 https://www.allthingslighting.org/?p=270 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 issue of LED Professional Review (www.led-professional.com). This update includes information from the published article. UPDATE 15/11/05 — […]

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]]> https://www.allthingslighting.org/photometry-and-photosynthesis/feed/ 0 Horticultural Lighting Metrics https://www.allthingslighting.org/horticultural-lighting-metrics/ https://www.allthingslighting.org/horticultural-lighting-metrics/#respond Fri, 15 Feb 2019 21:28:17 +0000 https://www.allthingslighting.org/?p=249 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 order to grow, and so we provided them with daylight and/or electric lighting. Given the […]

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]]> https://www.allthingslighting.org/horticultural-lighting-metrics/feed/ 0 Climate-Based Daylight Modeling https://www.allthingslighting.org/climate-based-daylight-modeling/ https://www.allthingslighting.org/climate-based-daylight-modeling/#respond Fri, 15 Feb 2019 00:58:29 +0000 https://www.allthingslighting.org/?p=186  Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published:  2016/03/26 daylight, n. The light of day. Apart from having a wonderfully circular definition in most English-language dictionaries, daylight really is just another form of illumination. As such, most people would expect lighting designers to be able to simulate daylight with the same ease […]

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]]> https://www.allthingslighting.org/climate-based-daylight-modeling/feed/ 0 Botanical Light Pollution https://www.allthingslighting.org/botanical-light-pollution/ https://www.allthingslighting.org/botanical-light-pollution/#respond Wed, 13 Feb 2019 01:04:08 +0000 https://www.allthingslighting.org/?p=144 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, resulting in potentially unacceptable levels of light pollution for astronomical observations. Unfortunately, LED streetlights emit more blue light on […]

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