Most of the following publications were authored or co-authored by team members and are relevant to lighting for plant applications.  They may not be specific to this LED research project.  For the scientific journal articles, you may contact the senior author for an electronic copy of the manuscript.  We thank Greenhouse Grower, Greenhouse Product News, GrowerTalks, and Photonics Spectra for their permission to post these articles on this site.

Industry Publications

Replacing incandescents with LEDs (2014) by Erik Runkle.  This article from GPN magazine discusses replacing incandescent lamps with commercial LED fixtures to deliver low-intensity lighting to regulate the photoperiod.

Lighting the future of young plants (2014) by Wes Randall and Roberto Lopez.  This article published in GPN magazine compares propagules grown under sole-source LED lighting and those grown in greenhouses with supplemental lighting.

Control flowering with LEDs (2014) by Qingwu Meng and Erik Runkle. Published in GrowerTalks, this article presents information on the use of a commercial LED lamp at regulating flowering of greenhouse crops in a coordinated grower trial.

Understanding the differences between photoperiodic and supplemental lighting (2013) by Roberto Lopez. Published in Greenhouse Grower, this article compares and contrasts the different types of lighting used in greenhouse crop production.

Comparing LED lighting to HPS lamps for plug production (2013) by Wes Randall and Roberto Lopez.  Published in Greenhouse Grower, this article discusses the use of LEDs to supplement sunlight in the production of plugs.

Comparing LED lighting to high-pressure sodium lamps (2013) by Chris Currey and Roberto Lopez.  This Greenhouse Grower article presents research on the use of LEDs and HPS lamps to supplement sunlight during propagation of cuttings.

Making LEDs easier to choose and use (2013) by David Kuack.  This article, published in GrowerTalks magazine, presents information and recommendations on LEDs from our team of researchers.

LEDs lower costs, boost crops inside greenhouses (2012) by Lynn Savage.  This article highlights our team's research with LEDs, including recent results and upcoming plans.  Published by Photonics Spectra.

LEDs: The future of greenhouse lighting! (2012) by Cary Mitchell, A.J. Both, Michael Bourget, John Burr, Chieri Kubota, Roberto Lopez, Robert Morrow, and Erik Runkle.  This article appeared in Chronica Horticulturae, the quarterly publication of the International Society for Horticultural Science, and provides an overview of LED technology and emerging applications in horticulture.

Getting the most out of light measurements (2010) by Christopher Currey, Ariana Torres, and Roberto Lopez. Do you know the difference between instantaneous light measurements and daily light integral? Learn how you can monitor, manage, and manipulate greenhouse light levels. Published in Greenhouse Grower.

Measuring daily light integral in a greenhouse (2010) by Ariana Torres and Roberto Lopez. Daily light integral (DLI) is the amount of photosynthetically active radiation received each day as a function of light intensity and duration. But do you know how to get the most out of DLI? A Purdue Extension publication.

Medición de luz diaria integrada en invernaderos (2010) por Ariana Torres y Roberto Lopez. La luz diaria integrada (DLI) es la cantidad de radiación fotosintéticamente activa recibida cada día en función de la intensidad de la luz y duración. ¿Sabe usted cómo obtener el máximo provecho de DLI? A Purdue Extension publication.

Measuring daily light integral (DLI) (2010) by Ariana Torres, Christopher Currey, Roberto Lopez, and James Faust. Learn how to properly measure DLI and species-specific DLI requirements.  A Purdue Extension publication.

The future of greenhouse lighting (2010) by Erik Runkle.  Light-emitting diodes are being rapidly developed for plant applications.  Here are some guidelines about desirable characteristics of LEDs for plant applications.  Published in Greenhouse Product News.

Strategies for supplemental lighting (2009) by Erik Runkle.  Different methods of greenhouse lighting have different purposes — sometimes to extend the photoperiod and sometimes to increase the daily light integral. Knowing their differences may help you make better choices for your operation. Published in Greenhouse Product News.

Maximizing supplemental lighting (2007) by Erik Runkle.  It’s no secret that increasing the daily light integral can result in higher quality greenhouse-grown plants. But do you know how to get the most value out of supplemental lighting?  Published in Greenhouse Product News.

Providing long days (2007) by Erik Runkle.  Crop development can be accelerated with the use of low-intensity lighting. Here are the answers to some common questions about photoperiodic lighting. Published in Greenhouse Product News.

Scientific Publications


Comparison of bedding plant seedlings grown under sole-source light-emitting diodes (LEDs) and greenhouse supplemental lighting from LEDs and high-pressure sodium lamps
(2015) by Wesley Randall and Roberto Lopez.

End-of-production supplemental lighting with red and blue light-emitting diodes (LEDs) influences red pigmentation of four lettuce varieties (2015) by Garrett Owen and Roberto Lopez.

Physiological responses of cucumber seedlings under different blue and red photon flux ratios using LEDs (2015) by Ricardo Hernández and Chieri Kubota.

An intermediate phytochrome photoequilibria from night-interruption lighting optimally promotes flowering of several long-day plants (2015) by Daedre Craig and Erik Runkle.

Physiological, morphological, and energy-use efficiency comparisons of LED and HPS supplemental lighting for cucumber transplant production (2015) by Ricardo Hernández and Chieri Kubota.

Controlling flowering of photoperiodic ornamental crops with light-emitting diode lamps: A coordinated grower trial
(2014) by Qingwu Meng and Erik Runkle.

Comparing flowering responses of long-day plants under incandescent and two commercial light-emitting diode lamps (2014) by Fumiko Kohyama, Cathy Whitman, and Erik Runkle.

Growth and morphological response of cucumber seedlings to supplemental red and blue photon flux ratios under varied solar daily light integrals (2014) by Ricardo Hernández and Chieri Kubota.

Comparison of supplemental lighting from high-pressure sodium lamps and light-emitting diodes during bedding plant seedling production (2014) by Wesley Randall and Roberto Lopez.

A moderate to high red to far-red light ratio from light-emitting diodes controls flowering of short-day plants (2013) by Daedre Craig and Erik Runkle.

Cuttings of Impatiens, Pelargonium, and Petunia propagated under light-emitting diodes and high-pressure sodium lamps have comparable growth, morphology, gas exchange, and post-transplant performance (2013) by Chris Currey and Roberto Lopez.

Comparison of intracanopy light-emitting diode towers and overhead high-pressure sodium lamps for supplemental lighting of greenhouse-grown tomatoes (2013) by Celina Gómez, Robert Morrow, C. Michael Bourget, Gioia Massa, and Cary Mitchell.

Plant lighting in controlled environments for space and earth applications (2012) by Cary Mitchell.

Using LEDS to quantify the effect of the red to far-red ratio of night-interruption lighting on flowering of photoperiodic crops (2012) by Daedre Craig and Erik Runkle.

Tomato seedling growth and morphological responses to supplemental LED lighting red:blue ratios under varied daily solar light integrals (2012) by Ricardo Hernández and Chieri Kubota.

Effect of end-of-day far-red light from a movable LED fixture on squash rootstock hypocotyl elongation (2012) by Zhen-Chao Yang, Chieri Kubota, Po-Lung Chia, and Murat Kacira.

End-of-day far-red light quality and dose requirements for tomato rootstock hypocotyl elongation (2010) by Po-Lung Chia and Chieri Kubota.

Effects of supplemental light quality on growth and phytochemicals of baby leaf lettuce (2009) by Qian Li and Chieri Kubota.

LED lighting in horticulture (2008) by Robert Morrow.  This HortScience manuscript discusses some of potential applications of using LEDs in horticulture crops and presents some of their advantages and disadvantages compared to traditional light sources.

Plant productivity in response to LED lighting (2008) by Gioia Massa, Hyeon-Hye Kim, Raymond Wheeler, and Cary Mitchell.  This HortScience paper presents information on the effects of light quality (including blue, green, red, and far red) on growth of horticulture crops including lettuce, radish, pepper, and spinach.

Theses and Dissertations

Using energy-efficient technologies to produce bedding plants and microgreens in protected and controlled environments (2014) by Joshua Gerovac. Purdue Univ. M.S. thesis.

Supplemental, end-of-day, and sole-source lighting from light-emitting diodes influences growth, morphology, and quality of annual bedding plant seedlings (2014) by Wesley Randall. Purdue Univ. M.S. thesis.

Investigating use of blue, red, and far-red light from light-emitting diodes to regulate flowering of photoperiodic ornamental crops (2014) by Qingwu Meng. Michigan State Univ. M.S. thesis.

Optimizing herbaceous annual cutting physiology, morphology, and rooting with supplemental light during propagation (2013) by Christopher Currey. Purdue Univ. PhD dissertation.

Growth and development of greenhouse vegetable seedlings under supplemental LED lighting (2013) by Ricardo Hernández. Univ. of Arizona PhD dissertation.

Determining effective ratios of red and far-red light from light-emitting diodes that control flowering of photoperiodic ornamental crops (2012) by Daedre Craig. Michigan State Univ. M.S. thesis.