Light Management in Greenhouses & Controlled Environments

Electric lighting is used in greenhouses to regulate the photoperiod to control flowering, or to increase growth to increase crop quality and yield.  It is also used for sole-source lighting of plants grown indoors. A few books and summary articles are below, followed by more in-depth articles on specific topics.

  • Light Management in Controlled Environments, a book edited by Roberto Lopez and Erik Runkle, contains 18 chapters written by 20 leading plant scientists about how light influences plant growth and development of specialty crops grown in greenhouses and controlled-environment growth rooms.
  • LED Lighting for Urban Agriculture, a book edited by Toyoki Kozai, Kazuhiro Fujiwara, and Erik Runkle that focuses on light-emitting diode (LED) lighting for the commercial production of horticultural crops in plant factories and greenhouses. It contains 32 chapters written by plant scientists and engineers in Asia and the U.S.
  • Use of Lighting to Accelerate Crop Timing by Erik Runkle and Matthew Blanchard, Michigan State University.
  • Greenhouse Glazing by A.J. Both, Rutgers University.

Resources

  • Indoor propagation

    Published on July 14, 2020

    High-value crops can be propagated indoors, inside refrigerated growth rooms and without sunlight. This article briefly lists some of the important considerations for an indoor propagation facility.

  • UV-transmitting greenhouse glazing

    Published on June 16, 2020

    Most greenhouse glazing plastics absorb UV radiation to enhance their longevity. However, plants grown under glazing that transmits UV are typically more compact, darker in color, and more resilient.

  • Common plant production acronyms

    Published on May 8, 2020

    This article briefly defines 20 acronyms (abbreviations formed from the initial letters of other words) commonly used when discussing controlled-environment production of plants.

  • What is the ideal lighting spectrum?

    Published on March 16, 2020

    With LEDs, we can tailor the light spectrum to elicit specific growth responses. This article discusses some of the considerations to identify an “ideal” plant lighting spectrum. As you will read, it’s highly situational.

  • LED fixture efficacy: A 2020 update

    Published on January 13, 2020

    As we enter 2020, there are already more than 50 LED products on the Design Light Consortium's Horticultural Lighting list of qualified products. The spectrum, amount of emitted light, and efficacy vary widely among fixtures.

  • How much supplemental lighting do you need?

    Published on December 17, 2019

    Several factors need to be considered when choosing a supplemental lighting system, and arguably the most important one is to determine what light intensity you want to deliver. This article provides steps on how to do that.

  • Including far red in an LED lighting spectrum

    Published on September 9, 2019

    Growers sometimes wonder whether it is beneficial to include far-red radiation in a light-emitting diode (LED) spectrum. Not surprisingly, it depends on the application and crop.

  • Managing light pollution

    Published on August 9, 2019

    While electric lighting is increasingly used in greenhouses to increase plant growth, yield, and quality, it can have unintended consequences to neighboring areas at night.

  • An overview of long-day lighting

    Published on July 17, 2019

    There are a lot of factors to consider for effective and efficient long-day lighting. This article provides a brief overview of when and how to deliver lighting to create long days inside greenhouses.

  • Is green light useful to plants?

    Published on June 17, 2019

    There is some confusion about the efficacy of green light at promoting photosynthesis. This article explains why and how green light is useful to plants.

  • The economics of lighting young plants indoors

    Published on June 12, 2019

    This article provides the framework of the economics of indoor lighting of young plants (transplants). It includes example costs for an indoor plant factory in Japan, and provides highlights for indoor lighting used by two commercial growers in the U.S.

  • Leafy greens: Sole-source light intensity

    Published on June 6, 2019

    Indoor production of leafy greens, Part 4 of 4: Research shows that providing high-intensity sole-source lighting to seedlings can increase harvestable yield of fresh-cut basil.

  • DLI 'requirements'

    Published on May 10, 2019

    This article provides daily light integral (DLI) guidelines to produce plants of at least moderate quality, assuming plants are grown at moderate temperatures.

  • A little far-red light goes a long way

    Published on May 3, 2019

    Part 4 of a 5-part series presents information on how a relatively low intensity of far-red light influences seedlings grown in fully controlled, indoor environments.

  • LEDs: Blue & far-red light

    Published on April 10, 2019

    Part 3 of a 5-part series summarizes results from an indoor lighting experiment with floriculture crop seedlings, where we determined whether blue light could nullify the effects of far red on stem elongation, without inhibiting flowering.

  • Leafy greens: Carbon dioxide injection

    Published on April 1, 2019

    Indoor production of leafy greens, Part 3 of 4: Is carbon dioxide enrichment beneficial for indoor production of basil seedlings?

  • Green and blue LED lighting

    Published on March 6, 2019

    Indoor production of leafy greens, Part 2 of 4: How green light affects lettuce growth can depend on blue and red light.

  • LEDs: Far red & light intensity interaction

    Published on March 4, 2019

    Part 2 of a 5-part series explains how far-red light and light intensity (the photosynthetic photon flux density) interact to influence growth of young plants indoors, under fully controlled environments.

  • Selecting an LED fixture

    Published on February 18, 2019

    With so many LED products now on the market, choosing the right lighting fixture is a crucial decision. This article discusses factors to consider when choosing an LED fixture for plant applications.

  • How green light affects floriculture crops

    Published on February 13, 2019

    Is green light really a safe light for floriculture crops? Researchers at Michigan State University find out the impact it has on crops that flower in response to the day length.

  • Lighting young plants indoors

    Published on February 4, 2019

    Part 1 of a 5-part series is an introduction to producing young plants indoors under fully controlled environments.

  • DLC requirements for LED fixtures

    Published on December 5, 2018

    This article highlights the DesignLights Consortium's (DLC's) requirements for testing and reporting horticultural lighting fixtures that contain light-emitting diodes (LEDs).

  • Growing ornamental seedlings under white LEDs

    Published on November 15, 2018

    Michigan State University researchers discuss the impacts of using white light on plant growth and human vision, as well as energy considerations when growing ornamental seedlings indoors.

  • White LEDs for plant applications

    Published on November 12, 2018

    Many horticultural lighting fixtures combine blue and red LEDs. However, there are merits to using fixtures that partly or completely contain white LEDs.