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United States Department of Agriculture

Agricultural Research Service

Research Project: DEVELOP MANAGEMENT TOOLS FOR EARLY STRESS DETECTION AND EFFICIENT AGROCHEMICAL UTILIZATION FOR PROTECTED HORTICULTURE CROPS

Location: Application Technology Research Unit

Title: Using flowering and heat-loss models for improving greenhouse energy-use efficiency in annual bedding plant production

Authors
item Runkle, Erik -
item Blanchard, Matthew -
item Frantz, Jonathan

Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 1, 2012
Publication Date: November 1, 2012
Citation: Runkle, E.S., Blanchard, M.G., Frantz, J. 2012. Using flowering and heat-loss models for improving greenhouse energy-use efficiency in annual bedding plant production. Acta Horticulturae. (ISHS)957:99-106.

Interpretive Summary: In cool, northern climates, annual bedding plants are typically produced in heated greenhouses from late winter through early summer. Several environmental settings can be manipulated during commercial production so that plants are in flower for predetermined market dates. We performed greenhouse-based experiments and then developed variety-specific crop models that predict the effect of mean daily temperature on time from transplant until first flowering. The crop models enable a user to identify the combinations of transplant dates and growing temperatures necessary for flowering to occur on chosen market dates. A computer program called Virtual Grower calculates greenhouse heating costs in over 800 US cities based on typical local weather conditions and greenhouse-specific characteristics such as building material, construction style, temperature set point, and heating system. Using the both the crop models and Virtual Grower, the temperatures and transplant dates that consume the least amount of energy for heating, on a per-crop basis, can be estimated for different market dates and locations. Not intuitively, warmer temperatures often resulted in the least amount of energy consumed due to reductions in production time. The later the desired market date or warmer local conditions, the differences between warm and cool production decreased. The amount of light provided had little effect (less than 1 day) on crop timing. This information can help growers determine the most energy-efficient production schedule for their greenhouse- and crop-specific situation.

Technical Abstract: In temperate climates, annual bedding plants are typically produced in heated greenhouses from late winter through early summer. Temperature, photoperiod, light intensity, and transplant date are commonly manipulated during commercial production so that plants are in flower for predetermined market dates. We performed experiments and then developed variety-specific crop models that predict the effect of mean daily temperature on time from transplant until first flowering. The crop models enable a user to identify the combinations of transplant dates and growing temperatures necessary for flowering to occur on chosen market dates. A computer program called Virtual Grower calculates greenhouse heating costs in over 800 US cities based on user-defined inputs such as building material, construction style, temperature set point, heating system, and typical weather at the selected location. Using the crop models and Virtual Grower, the temperatures and transplant dates that consume the least amount of energy for heating, on a per-crop basis, can be estimated for different market dates and locations. This information can help growers determine the most energy-efficient production schedule for their greenhouse- and crop-specific situation.

Last Modified: 7/28/2014
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