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Growth, flowering and climate (81)

20 Oct 2023

USDA FNRI: A Closer Look at the Effect of White LEDs on Plant Performance

Jiyong Shin, Nathan Kelly, and Erik S. Runkle, Michigan State University

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.

Runkle WhiteLEDStudy Article (900 KB)

20 Oct 2023

USDA FNRI: Several Consequences of Growing Too Cool

Erik Runkle, Michigan State University

Discussion of the consequences of lowering greenhouse air temperature including slower rooting during propagation and longer crop production time.

Runkle GrowingTooCool Article (388 KB)

20 Oct 2023

USDA FNRI: The Importance of Transpiration

Erik Runkle, Michigan State University

Discussion of the specific functions of transpiration, as well as the different cultural and environmental factors in controlled environments that can influence the process.

Runkle Transpiration Article (2656 KB)

20 Oct 2023

USDA FNRI: A Focus on Root-zone Temperature

Iro Kang & Roberto Lopez, Michigan State University

Successfully rooting tropical foliage plants and succulents.

Lopez RootzoneHeating Article (396 KB)

20 Oct 2023

USDA FNRI: A Focus on DLI

Iro Kang & Roberto Lopez, Michigan State University

Successfully rooting tropical foliage plants and succulents.

Lopez DLIFocus Article (1586 KB)

20 Oct 2023

USDA FNRI: Photoperiod Management

Roberto Lopez, Michigan State University

Flower induction of specialty cut flowers.

Lopez Photoperiod Article (2235 KB)

20 Oct 2023

USDA FNRI: The Problem With Purple

Charlie Smith and Roberto Lopez, Michigan State University, Nathan Jahnke, Ball Horticulture, and Colin Brice, Philips Horticulture LED Solutions

Collaborative research determines how to prevent chlorosis and undesirable purple pigmentation that can sometimes develop on cuttings rooted under LED supplemental lighting.

Lopez PetuniaPurpling Article (492 KB)

20 Oct 2023

USDA FNRI: Biofilm management in irrigation lines and hydroponic lettuce solutions using sanitizing chemicals

Paulo Rodrigues, University of São Paulo, Maria Fernanda Trientini and Paul Fisher, University of Florida

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.

Fisher Biofilm Article (563 KB)

20 Oct 2021

Michigan State University Crop Management Articles

Erik Runkle, Michigan State University

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)

22 Oct 2020

Crop Management Articles from Michigan State

Erik Runkle, Michigan State University

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)

1 Aug 2019

Heat Delay in Poinsettias

Paul Fisher (University of Florida), Jim Faust, Michael Tierney (Clemson University)

Heat Delay in poinsettias and how to mangage it.

HeatDelayinPoinsettias GPN 0819 (1376 KB)

25 Oct 2016

Grower Articles on LED Lighting and Effect on Plant Growth

Erik Runkle (Michigan State University)

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)

25 Oct 2016

Grower Articles on Plant Boundary Layer and VPD vs. Relative Humidity

Erik Runkle (Michigan State University)

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)

25 Oct 2016

Grower Articles on Sole-Source Lighting in Horticulture

Roberto G. Lopez (Michigan State University) and Joshua K. Craver (Purdue University)

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)

26 Nov 2015

Rose harvest tools - ReglaDeCosecha y FechaDeRosa

Paul Fisher, University of Florida

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.

FechaDeRosa1 (685 KB) ReglaDeCosecha1 (269 KB)

20 Nov 2015

FlowersOnTime: A Computer Decision-Support Tool for Floriculture Crop Producers

Paul Fisher (University of Florida), Erik Runkle (Michigan State University), Matthew Blanchard (Michigan State University), John Erwin (University of Minnesota), Bruce MacKay (thomasBaine Ltd.)

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.

FlowersOnTimeV14 (177 KB)

10 Aug 2012

Blueberries as Ornamental Edibles

Paul Fisher

Blueberries provide a niche crop that combine consumer interest in edible gardening with sustainability and low-care perennials.

Blueberries as ornamental edibles article (1248 KB)

21 Oct 2010

Hormonal and cell division analyses in Watsonia lepida seedlings

John Erwin (University of Minnesota)

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.

JPLPH50749 (624 KB)

20 Oct 2010

Floral ontogeny of Brunonia australis (Goodeniaceae) and Calandrinia sp. (Portulacaceae)

Robyn L. Cave (The University of Queensland), Colin J. Birch (University of Tasmania), Graeme L. Hammer(The University of Queensland), John E. Erwin (University of Minnesota) and Margaret E. Johnston (The University of Queensland)

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.

BT09211 (929 KB)

30 Nov 2009

Providing long days with CFLs

Sonali Padhye (Univ. of Florida) and Erik Runkle (Michigan State Univ.)

We compare crop responses to lighting with incandescent lamps with that from compact fluorescent lamps (CFLs).

Providing LD with CFLs (752 KB)

30 Nov 2009

Maximizing supplemental lighting

Erik Runkle (Michigan State Univ.)

Learn some basic concepts about how to maximize use of supplemental (high intensity) lighting of greenhouse crops.

Maximizing supplemental lighting (163 KB)

30 Nov 2009

Manipulating light in the greenhouse

Matthew Blanchard and Erik Runkle (Michigan State Univ.)

This article presents research-based information on how plants respond to a rotating (cyclic) high-pressure sodium lamp to create a long photoperiod.

Rotating HPS lamps (2790 KB)

30 Nov 2009

Why use Virtual Grower?

Erik Runkle (Michigan State Univ.) and Jonathan Frantz (USDA-ARS)

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.

Virtual Grower (96 KB)

30 Oct 2009

Energy-Efficient Poinsettia Production

Erik Runkle (Michigan State Univ.) and Jim Faust (Clemson Univ.)

With the volatile price of fuel, finding ways to limit energy consumption in the production process of poinsettia has never been more important.

EnergyEfficientPoinsettias (152 KB)

28 Oct 2009

Managing Light During Propagation

Roberto Lopez and Erik Runkle (Michigan State University)

Michigan State University research examines how environmental factors - especially light - influence the rooting and growth of vegetative annual cuttings.

LightinginPropagationMSU (909 KB)

28 Oct 2009

Growing Crops Cooler

Erik Runkle (Michigan State University) and Paul Fisher (University of Florida)

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.

GrowingCropsCooler (165 KB)

28 Oct 2009

Supplemental Lighting Can Increase Production of Vegetative Cuttings

Paul Fisher and Caroline Donnelly (University of Florida)

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.

LightingofstockPlants (180 KB)

28 Oct 2009

Ten Aspects of Lighting Spring Crops That Can Help Your Bottom Line

Erik Runkle (Michigan State University) and Paul Fisher (University of Florida)

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.

LightingSpringCrops (374 KB)

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