Click on a topic in the menu to view specific articles in pdf format published in trade magazines. Articles posted with permission from Greenhouse Product News, Greenhouse Grower, Greenhouse ManagementGrowerTalks, and other horticulture magazines. All articles are in .pdf format.

  • 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.

  • 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.

  • Crops suitable for vertical farming

    Published on April 10, 2019

    The costs to build and operate an indoor (vertical) farm are high, so only certain types of crops are potentially profitable. This articles discusses some some of the crop characteristics that lend themselves to indoor production.

  • 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.

  • Success with PGRs

    Published on March 18, 2019

    Regardless of the desired outcome, successful use of a plant growth regulator (PGR) requires multiple considerations and attention to detail. This article summarizes practices to obtain the best results from your PGR applications.

  • 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.

  • Greenhouse disease management 2019

    Published on February 4, 2019

    Suggested treatments for common greenhouse pathogens of floriculture crops including botrytis, powdery mildew, downy mildew, phytophthora, pythium, rhizoctonia, etc. This information is for educational purposes only.

  • 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.

  • Greenhouse pest management with insecticides

    Published on February 1, 2019

    Research-based information is presented on how to manage greenhouse insects and other pests including thrips, aphids, whiteflies, mites, fungus gnats, and mealybugs.

  • Ethylene in floriculture

    Published on January 7, 2019

    Ethylene can be a harmful contaminant in greenhouses and during shipping, but there are also situations when ethylene can elicit desirable responses in greenhouse crop production.

  • 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.

  • Purple vs. pink vs. white LED fixtures

    Published on September 10, 2018

    LED fixtures that emit a purplish light are usually less preferred by people, but are often the most efficient at converting electricity into light useful to plants.

  • Using a GA to increase plant height

    Published on August 8, 2018

    Regardless of the cause, the most common technique to increase plant height of containerized flowering plants is an application of gibberellic acid by someone certified as a pesticide applicator.

  • An update on LED lighting efficacy

    Published on July 5, 2018

    In plant lighting, the photosynthetic photon efficacy of a fixture quantifies how effectively a fixture converts electricity into light useful for photosynthesis. This article provides an update the efficacy values of LEDs as of 2018.

  • Horticultural lighting applications

    Published on June 11, 2018

    This article summarizes the different lighting applications and characteristics used in horticulture, including in greenhouses and indoors.

  • Causes of flower bud abortion

    Published on March 14, 2018

    There are many potential causes to flower bud abortion, including pests, environmental factors, and cultural factors.

  • Temperature integration

    Published on February 5, 2018

    Plants integrate and respond to temperature over an extended period, and not just the day or night temperature.

  • Maximize the benefits of supplemental lighting

    Published on January 8, 2018

    Purchasing, installing, and operating supplemental greenhouse lighting is fairly expensive. Here are some tips and considerations to maximize your supplemental lighting system.

  • Does light quantity trump light quality?

    Published on December 5, 2017

    Some of our recent research confirms that light quality (such as the ratio or red to far red) has a greater effect on plant growth when light intensity is low than when it is high.

  • Factors that influence leaf coloration

    Published on November 15, 2017

    Growers usually focus on quality attributes that relate to flowering, but this article reviews cultural and environmental factors that influence foliage color.

  • Developing new plant lighting standards

    Published on October 23, 2017

    Standards are developed so there is consistency and conformity in products to improve confidence and comparability in new technologies.

  • Investment considerations for greenhouse lighting

    Published on October 11, 2017

    Many growers install and operate supplemental (photosynthetic) lighting to increase crop quality and yield. This article describes some of the factors to consider when investing in a supplemental lighting system for greenhouse crop production.

  • Supplemental greenhouse lighting: LED or HPS?

    Published on September 20, 2017

    Researchers at Michigan State University see if the results from producing high-quality seedlings with LEDs justify the higher capital outlay for installation.

  • Sole-source lighting of plants

    Published on September 13, 2017

    Sole-source lighting is a term used to describe the deliver of light to plants that do not also receive light from the sun. In other words, electric lighting is delivered indoors and provides the sole source of light for plant growth and development.

  • Lighting plans: Their generation and importance

    Published on August 17, 2017

    Light intensity and uniformity are critical to successful production of plants. This article describes how lighting plans are developed, and why they are so important when comparing lighting technologies.

  • Supplemental and sole source LED lighting

    Published on August 9, 2017

    Joining me today is Erik Runkle, professor at Michigan State University. Erik is well known in this magazine for his “Technically Speaking” column appearing inside the back cover.

  • Plant lighting efficiency and efficacy

    Published on July 10, 2017

    Plant lighting continues to be a hot topic, especially as light-emitting diode (LED) technology continues to advance. Learn more about how electric lamps convert electricity into photons of light useful to plants.

  • Growing plants with green light

    Published on June 7, 2017

    Green light can be defined as radiation with wavelength between 500 and 600 nanometers. Green light is within the photosynthetically active waveband of 400 to 700 nm, yet its effects on plant growth and development are not well understood.

  • Understanding how PGRs work

    Published on May 17, 2017

    Plant growth regulators are chemical compounds that regulate various growth and developmental processes in plants, such as seed germination, rooting, branching, flowering, fruit development, dormancy and plant growth habit.

  • Asclepias tuberosa - Butterfly weed

    Published on April 12, 2017

    Several species of milkweed, or asclepias, are native to North America, and this year the Perennial Plant Association has chosen one of them as Perennial Plant of the Year: Asclepias tuberosa.

  • The importance of light uniformity

    Published on March 3, 2017

    Managing light is obviously critical to the production of crops grown in controlled environments. When considering the different dimensions of light, we often overlook the importance of light uniformity.

  • Far red is the new red

    Published on February 6, 2017

    Adding far red to red and blue light from LEDs brings control of plant growth to the next level.

  • Effects of blue light on plants

    Published on February 2, 2017

    Blue light is usually referred to as radiation with wavelengths between 400 and 500 nanometers. This waveband is within the visible spectrum, has relatively high energy, and has pronounced effects on plant growth and flowering.

  • Vertical farming

    Published on January 9, 2017

    Vertical farming is the production of plants in multiple vertical layers indoors, such a controlled-environment buildings, repurposed warehouses, growth chambers and shipping containers.

  • Bedding plants with high base temperatures

    Published on December 14, 2016

    In the late winter and spring, many greenhouse growers produce a wide variety of species and cultivars, many of which are annual bedding plants. Crops can have different growing and flowering requirements, so plants shouldn’t all be grown the same way.

  • Know your light levels

    Published on November 29, 2016

    Follow these guidelines to accurately measure photosynthetic light levels with meters in the greenhouse.

  • The best tool for the job

    Published on November 22, 2016

    Know your options to choose the optimal greenhouse shading material for your operation.

  • High tunnel and outdoor production of bedding plants

    Published on November 17, 2016

    As greenhouse space becomes limited in the spring, you may consider using outdoor spaces and high tunnels. Read on for insight into the benefits and risks associated with these growing strategies.

  • Evaluating greenhouse supplemental lighting

    Published on November 17, 2016

    Researchers at Purdue and Michigan State University compare young and finished plant production under LED toplighting and HPS lamps to determine which source is most effective.

  • The economic viability of LED lighting

    Published on October 7, 2016

    Determine whether LED lighting is right for your operation by considering seven important factors that impact return on investment.

  • Fascination on poinsettia

    Published on August 8, 2016

    Did you hit your poinsettias with too much growth retardant? This Michigan State University research shows how to recover using products that contain gibberellic acid.

  • Red light and plant growth

    Published on August 7, 2016

    Many LED fixtures developed for plant growth applications emit a large proportion of red light. Learn about the roles of red light in photosynthesis, extension growth, and flowering, as well as human perception.

  • Juvenility in perennials

    Published on June 29, 2016

    Plants started by seed have a juvenile phase and they must develop to a certain maturity before they attain the capacity to flower.

  • A closer look at far-red radiation

    Published on May 7, 2016

    Far-red light can be defined as photons with wavelengths from 700 to 800 nanometers. It can promote extension growth and flowering, and at least indirectly increase growth.

  • Diffused glass

    Published on April 23, 2016

    Growers need to weigh the advantages of diffused glass with its cost considering their greenhouse location, production periods, and types of crops grown.

  • Efficacy of lamp types at controlling flowering

    Published on February 23, 2016

    This article summarizes the effectiveness of low-intensity lighting from different lamp types at regulating flowering of a wide range of ornamental crops based primarily on research performed at Michigan State University.

  • Improve rooting of cuttings

    Published on January 19, 2016

    Successful rooting of cuttings requires careful management of the environment, especially air and media temperature, humidity and light.

  • Environment and PGR interactions

    Published on December 17, 2015

    When plant growth regulators (PGRs) are applied as sprays, their efficacy can be greatly influenced by the environment. Understanding how environmental factors influence PGR spray efficacy can lead to more effective and predictable plant responses.

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