Downloadable resources from completed projects are available from this page.
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Evaluation of the influence of light at the same total intensity (photon flux density, or PFD) using three different types of white LEDs, combined with light from red LEDs, while keeping the blue PFD constant in kale and lettuce.
Discussion of the consequences of lowering greenhouse air temperature including slower rooting during propagation and longer crop production time.
An overview of some major considerations when developing an indoor lighting system for crop production.
Discussion of the specific functions of transpiration, as well as the different cultural and environmental factors in controlled environments that can influence the process.
Developments in LED technology and lighting control systems.
Successfully rooting tropical foliage plants and succulents.
Successfully rooting tropical foliage plants and succulents.
Flower induction of specialty cut flowers.
Collaborative research determines how to prevent chlorosis and undesirable purple pigmentation that can sometimes develop on cuttings rooted under LED supplemental lighting.
Evaluation of the effects of four sanitizers on (A) biofilm control within mist irrigation lines, and (B) biofilm and plant growth in hydroponic lettuce cultivation.
A collection of articles from the past year by Dr. Erik Runkle from Michigan State University that deal with applications of the light spectrum, LED and supplemental lighting, and more including the 2021 Indoor Lighting Guide.
FRA 2021 Runkle Indoor lighting guide mid res (8000 KB) FRA 2021 Runkle Increasing the DLI (469 KB) FRA 2021 Runkle Hidden benefits of lighting (280 KB) FRA 2021 Runkle Spectrum applications (184 KB) FRA 2021 Runkle Lamp PPF (172 KB) FRA 2021 Runkle LED challenges (5112 KB) FRA 2021 Runkle LEDs more than umol-J (306 KB) FRA 2021 Runkle MakingSenseofLightSensors (895 KB)
A collection of articles from the past year by Dr. Erik Runkle from Michigan State University that deal with leaf purpling, how photosynthesis and respiration affect plant growth, and the challenges of growing vertically inside greenhouses.
FRA 2021 Runkle Purple leaves (356 KB) FRA 2021 Runkle Maximize Pn minimize Rs (263 KB) FRA 2021 Runkle Growing vertically (414 KB)
A collection of articles from the past year by Dr. Erik Runkle from Michigan State University that deals with plant diagnostics, propagation, height control, and quality floricultural crops.
Propagation pointers (277 KB) Poor quality floricultural crops (272 KB) Perennial height control (265 KB) Indoor propagation (275 KB) Importance of plant diagnostics (726 KB)
A collection of articles from the past year by Dr. Erik Runkle from Michigan State University that deal with supplemental light, light pollutin, and UV transmitting greenhouse glazing.
UV-Transmitting greenhouse glazing (201 KB) Managing light pollution (238 KB) Including far red in lighting spectrum (278 KB) How much supplemental light (189 KB)
Annika E. Kohler, graduate student, and Dr. Roberto Lopez from Michigan State University share the latest findings on supplemental lighting's effect of rooting of herbs.
Annika Kohler, graduate student, and Dr. Roberto Lopez from Michigan State University determine the minimum duration of far-red radiation required during plug production to induce long-day requiring plants into flower after transplant.
studying the effects of light quality on plant growth.
Heat Delay in poinsettias and how to mangage it.
Evaluating the growth (fresh and dry mass), accumulation of key phytochemical constituents (leaf photosynthetic pigment and nitrate content), and aesthetic quality (elongation and pigmentation) of red-leaf lettuce (Lactuca sativa) grown from transplant to a harvest stage in an indoor environment.
An economic analysis of growing young plants indoors with LEDs.
Research about plant responses to far red and light intensity.
Discusses lighting for growing young plants indoors using LEDs.
Understanding the ins and outs of the indoor food gardenig market.
Getting a Piece of the Indoor Food Gardening Market-Greenhouse Product News (1214 KB)
See the grower articles on LED lighting:
1. Lighting Metrics … And What Matters, GPN, October 2015
2. Diffused Glass, GPN, April 2016
3. A Closer Look at Far-Red Radiation, GPN, May 2016
4. The Economic Viability of LED Lighting, Greenhouse Grower TECHNOLOGY, September/October 2016
Lighting metrics... and what matters (106 KB) Economic viability of LED lighting (210 KB)
See the grower articles on LED lighting and effect on plant growth:
1. Keys to Successful Seedling Production, GPN, November 2015
2. Managing Light to Improve Rooting of Cuttings, GPN, September 2016
3. Juvenility in Perennials, GPN, June 2016
4. Efficacy of Lamp Types at Controlling Flowering, GPN, February 2016
5. Red Light and Plant Growth, GPN, August 2016
6. Success with Succulents, GPN, July 2016
Keys to successful seedling production (190 KB) Success with succulents (1169 KB)
See the two climate related articles:
1. The Boundary Layer and Its Importance, GPN, March 2016
2. VPD vs. Relative Humidity, Heidi Wollaeger & Erik Runkle, Inside Grower
The boundary layer and its importance (136 KB) VPD versus relative humidity (147 KB)
See the grower articles on LED lighting and effect on plant growth:
1. Sole-Source Lighting In Horticulture: Microgreens Production, Joshua K. Craver and Roberto G. Lopez, Greenhouse Grower, September 2015
2. Sole-Source Lighting In Horticulture: Bedding Plant Plug Production, Joshua K. Craver and Roberto G. Lopez, Greenhouse Grower, October 2015
3. The Impact of DLI, Light Quality and Photoperiod on Bedding Plant Flowering Response, W. Garrett Owen and Roberto G. Lopez, GPN, August 2016 (Note: the title was modified)
4. Evaluating Greenhouse Supplemental Lighting For Young And Finished Plant Production, Joshua K. Craver and Roberto G. Lopez, Greenhouse Grower, November 2016
Sole-source lighting in horticulture microgreens production (4770 KB) Evaluating greenhouse supplemental lighting for young and finshed plants (1684 KB)
Determining if sample container material or storage temperature affect paclobutrazol stability over time.
Spreadsheet tools to predict time to harvest for cut flower roses.
Unas herramientas de Excel para predecir el tiempo de la cosecha de rosas de corte.
This computer decision-support tool quantifies how a change in greenhouse air temperature would affect flower timing for a range of floriculture species.
This information is helpful when growers are considering reducing greenhouse air temperature in order to save on heating fuel cost, or because they want to achieve a target flowering date by manipulating temperature.
The pdf file contains detailed laboratory procedures for the LimeR protocols and provides instructions to use the Excel files. Materials for conducting LimeR series tests are also provided.
Overall LimeR Model Oct 2012.xlsx
This Excel file combines the LimeR protocols and their underlying research and chemistry into a prototype Excel spreadsheet model called 'Overall LimeR Model'. Please refer to pages 32-37 in the 'LimeR Protocols.pdf' for details.
LimeR tests 1h.xls
This Excel file can be used for both LimeR Substrate Lime Requirement Test and LimeR Lime Reactivity Test. This Excel file contains 'Lime reactivity test' worksheet and 'Substrate lime requirement test' worksheet. For details, please refer to page 13 and page 17 in the 'LimeR Protocols.pdf'.
Residual Lime Calculator.xls
This Excel is to be used for the 'LimeR Residual Lime Calculator'. The Excel file contains 'System Calibration', 'Standard Curve' and 'Residual Lime Calculator' worksheets. Please refer to page 21 in the 'LimeR Protocols.pdf' for details.
Overall LimeR Model Oct2012.xlsx (226 KB)
LimeR tests 1h (300 KB) Residual Lime Calculator (205 KB) LimeR Protocols (2243 KB)
Blueberries provide a niche crop that combine consumer interest in edible gardening with sustainability and low-care perennials.
The regeneration ability, cell division activity, auxin and cytokinin content of seedling regions and hypocotyl subsections of Watsonia lepida were studied. A total of 21 different cytokinins or conjugates were found in seedlings, with the highest cytokinin content in meristematic regions (root and shoot apical meristems). The greatest contribution to the cytokinin pool came from the biologically inactive cZRMP, suggesting that significant de novo synthesis was occurring. Five different auxins or conjugates were detected, being concentrated largely in the shoot apical meristem and leaves, IAA being the most abundant. Analysis of hypocotyl subsections (C1-C4) revealed that cell division was highest in subsection C2, although regeneration in vitro was significantly lower than in subsection C1. Anatomically, subsection C1 contains the apical meristem, and hence has meristematic cells that are developmentally plastic. In contrast, subsection C2 has cells that have recently exited the meristem and are differentiating. Despite high rates of cell division, cells.
Floral ontogeny of Brunonia australis Sm. ex R.Br. (blue pincushion) and Calandrinia sp. (not yet fully classified) was investigated by scanning electron microscopy to assist further efforts for manipulating flowering of these potential floriculture crops. This is the first work to study floral initiation and the stages of flower development for these species.
We compare crop responses to lighting with incandescent lamps with that from compact fluorescent lamps (CFLs).
Learn some basic concepts about how to maximize use of supplemental (high intensity) lighting of greenhouse crops.
This article presents research-based information on how plants respond to a rotating (cyclic) high-pressure sodium lamp to create a long photoperiod.
Now in version 2.5, the Virtual Grower greenhouse simulation software translates your structure's data to help calculate costs and make choices to be more energy efficient.
With the volatile price of fuel, finding ways to limit energy consumption in the production process of poinsettia has never been more important.
This scientific article was originally published in Acta Horticulturae 718:461-468. This article presents insight view of a quantitative model to describe reaction of lime over time.
This scientific article was originally published in HortScience 42:1268-1273, 2007. The objective of this study was to develop reactivity indices to describe the pH response for liming materials incorporated into container substrates.
This scientific article was originally publised in HortScience 42:1685-1689, 2007. This article decribes detailed procedures to measure residual lime in container media using a gasometric system.
Michigan State University research examines how environmental factors - especially light - influence the rooting and growth of vegetative annual cuttings.
With the high price of fuel, many growers in cold climates have lowered their temperature setpoints to save money. However, we explain how a lower greenhouse temperature increases crop time, which can sometimes actually increase overall fuel cost.
Peak production of vegetative cuttings for bedding plants in the U.S. (November to March) occurs during the period of lowest sunlight. One option to provide more light, and therefore increase both photosynthesis and yield of cuttings, is to use highpressure sodium (HPS) lamps. The key question for growers, however, is whether the increased yield in cuttings will more than offset the cost of purchase, installation, and operation of HPS.
Light is key to producing quality crops and early flowering of long-day plants. But specifically how can you turn greenhouse lighting of spring crops into profit? The following pointers can help.
How much lime does a particular batch of growing medium require to achieve a target pH? This video presentation shows details of a protocol to determine the lime requirement of a batch of growing media using a calcium hydroxide:pH-titration curve.
How reactive is your lime source? This video presentation shows a protocol to test the reactivity of a liming material in horticultural substrates, to allow prediction of pH changes over time.
Unreacted residual lime in container media provides buffering (resistance to change) in media-pH during crop production. This video presentation shows a substrate test protocol to measure how much residual lime is in a substrate sample, by applying HCl acid to a substrate sample, and measuring the evolved CO2 gas with a gasometric method.
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