This session generously sponsored by:
Xiuming Hao
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LED - 24-Hour Lighting in Greenhouse Vegetable Production Artificial lighting is needed to supplement natural sunlight to allow successful production of greenhouse vegetables during the winter in Canada because of poor sunlight conditions. Yield and quality improvement by the supplemental light is mostly determined by the total amount of light supplemented during a day (daily light integral (DLI) – intensity x photoperiod). Therefore, it would be more economical to use long photoperiod (up to 24-h) of low intensity lighting to supplement the desired DLI because it can reduce the capital cost for light fixtures, allow more efficient use of the heat released from the light fixtures (by spreading it over 24 h and contributing to heating during the night), and facilitate the application of blackout curtain to prevent light pollution. However, lighting longer than 17-h causes significant injury on greenhouse fruit vegetables. In this presentation, Dr. Xiuming Hao will discuss newly discovered LED lighting strategies which allow for injury-free production of greenhouse tomatoes and cucumbers with 24-h (continuous) lighting. These strategies also have a great potential to reduce peak power demand and electricity costs, in addition to the benefits on reducing light fixture capital costs and light pollution and improving energy efficiency in year-round greenhouse vegetable production. |
David Llewellyn Research Associate, University of Guelph, ON |
End of Day Lighting for Potted Crops Our previous studies in growth chambers have indicated the potential for targeted spectrum treatments, when applied at low fluence rates outside of the assimilation photoperiod, to manipulate flowering responses of some crops. A 2020 trial tested whether similar end-of-day (EOD) spectrum treatments could influence flowering in some greenhouse-grown potted floriculture crops from different photoperiod response groups. Llewellyn presents the results of this 2020 trial and related trials from our lab and discusses potential commercial implications for the floriculture industry. |
Roselynne Labbe
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Like Moth to a Flame: How artificial lights affect arthropods in the greenhouse environment Canada’s northerly latitude means that less than half the quantity of solar radiation reaching crops at the peak of summer, is delivered in the deep of winter. This massive difference has clear implications for greenhouse crop production, and along with the increasing number of vertical farms, is one of the main drivers of today’s use of artificial HPS and LED lights for protected crop production. Despite this, little research to date has systematically examined how these new light environments can impact greenhouse crop protection – both the good bugs and the bad. We know light is important to arthropods, such as when moths are drawn to flames. But how important is it really to greenhouse pest management? In this session, we will discuss how light quality, quantity and duration can all affect individual insects as well as their populations and sometimes tip the balance towards achieving successful greenhouse pest management. We will present findings from past and ongoing research that are now shaping the way we both select and apply biocontrol agents under artificial light environments and discuss where future research is needed to improve both year-round and vertical crop protection. |
*approximately 30 minute sessions