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Hydroponic Lettuce Workshop II at Purdue

Hydroponics Workshop II Greenhouse and Indoor based hydroponics for growing green leaf produce is rapidly growing near urban areas in Indiana. To bridge the gap in learning and increase the competitiveness of Indiana and Midwestern growers, Purdue Extension specialists and researchers in the department of Horticulture and Landscape Architecture have developed workshops that provide experiential learning to growers. Purdue Extension and the department of Horticulture and Landscape Architecture welcomes everyone interested to attend the second hydroponics workshop scheduled for September 8, 2017 at WSLR 116, 170 S. University St., Purdue University, West Lafayette, IN 47907. This workshop focuses on supplemental lighting for winter production, strategies for successful production in indoor or vertical farms, biological pest control, fertilizer recipes and injectors and ongoing research in greenhouses.             Registration is free but required to attend the workshop. Visit or contact Ms. Lori Jolly-Brown at 765-494-1296 for[Read More…]

Our Research Highlights

Click on the link to learn out our research highlights: Phenotyping work update  

Spectral reflectance for measuring crop N status

Nutrient solution concentration for hydroponically grown lettuce in plant factories and greenhouses is adjusted based on electrical conductivity (EC) of the recycled solution. A better approach is to adjust nutrient solution concentration using plant-based measurements.   We are conducting further research to study whether crop reflectance signature can be used to identify nutrient requirements of crops    

Fertilizer requirements of crops using imaging

Lower fertilizer application rates can influence crop quality while higher rates can pose health-risk issues in humans when consumed (ex: spinach and lettuce) and increase plant susceptibility to pests.  Therefore, plants should be supplied with fertilizer in the amounts they need to grow optimally. We are investigating methods to fertilize plants based on the plant nutrient demand.  Our approach is to non-invasively measure crop growth rate using RGB imaging and supply nutrients that match the crop growth rate.  We are currently using this approach for tomato and lettuce.  Using imaging we can estimate crop dry weight on a daily basis.  This can be used to predict the crop growth rates and the amount of nutrients needed by the plant to sustain the current growth.  Below is an example of imaging work done on tomato and relation between image based metric and crop dry weight.  We are developing simple camera and Lysimetry based system that can capture crop growth rate and crop water use. [Read More…]

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Improving supplemental light use efficiency of greenhouse crops

Supplemental lighting is required to produce quality crops inside greenhouses in the northern US.  The energy costs for supplemental lighting can be quite significant.  For example, to add 5 moles of supplemental light per day using 1000 W HPS lamps during mid Nov to mid Mar for an acre of greenhouse can cost $25000.  This makes lighting one of the most expensive input for production.  In addition, only a fraction (1-3%) of supplemental light is actually used by plants in photosynthesis.  Therefore it is important to improve supplemental light use efficiency of plants for ‘sustainable’ crop production.  Our research is focused on identifying environmental factors that transiently reduce supplemental light use efficiency in greenhouses and mitigating these transient stressors during production.  We use a combination of remote sensing techniques to identify supplemental light use efficiency of plants and transient environmental stressors experienced by plants in greenhouses.  Our goal is to develop affordable technologies that can be easily transferred to the greenhouse[Read More…]

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