Dharti Thakulla (PhD student), Carly Nelson (research associate), and Marcus Beck (Agricultural and Biological Engineering BS student) are researching the implementation of ozone and non-thermal plasma technology for water treatment. Microbial contamination of the nutrient solution is a key challenge faced by hydroponic growers using recirculating systems. Ozone and non-thermal plasma technologies have been reported to aid in microbial sanitation and plant yield. However, it is important to consider and establish the correct method, dosage, and frequency of incorporating these technologies into hydroponic systems to avoid unwanted effect on plant growth or development. Through this project we aim to study the physio-chemical properties of ozone and plasma activated water and their effects on crop yield, sanitation, oxygen stability, and fertilizer interactions for hydroponic production.

Harrison Meekins, an M.S student in Environmental Horticulture, is researching heavy metal uptake and contamination in hemp. Heavy metals are heavily regulated by the EPA as a contaminant and pose a significant threat to hemp growers because of its tendency to accumulate heavy metals. Harrison is working to develop methods that growers can use to determine the presence of heavy metals in their crops accurately and reliably. One method is developing a bioassay that can be used to track the uptake of heavy metals into plant tissue. Another method is comparing different soil testing methods by their ability to extract and detect the presence of heavy metals in growing media. This will provide hemp growers with more knowledge to detect and combat heavy metal contamination to their plants.

Several students and staff at University of Florida, University of Arkansas, and University of Georgia are collaborating on balancing ion levels in recirculating nutrient solutions. Recirculating nutrient solutions are hard to manage because of the complex interactions between inputs and outputs of ions such as water quality, water treatment, solution pH, and acid type. This project aims to develop a mass balance model and easy-to-use decision-support tool that can customize solutions according to grower conditions to reduce fertilizer and water costs and the environmental impact of nutrient solution drainage.

Mario Molina (Agricultural and Biological Engineering B.S. student) is collaborating with Sofia Gomez (an M.S. student at Purdue University) and Dr. Celina Gomez at Purdue University to develop an automated environmental control system (light cart) for growing transplants to conduct research, modeling how factors such as vapor pressure deficit (VPD) affect leaf temperature and water loss during propagation. Vertical farming offers the ability to manipulate the propagation climate to optimize the growing environment of hard-to-root plants. However, this comes with an increased cost for growers that needs to be offset by reducing the propagation time and improving the quality of transplants compared to other propagation methods. The use of light carts as a research tool will enable to conduct several projects, modeling factors such as VPD, that play a key role on water loss of unrooted plats with the aim of optimizing the climate for indoor vertical farming propagation.

Daniel Crawford, an Agricultural and Biological Engineering B.S. student at the University of Florida, is researching climate sensors for propagation greenhouses. Production of seedlings, cuttings, and tissue culture transplants requires precise control of light, temperature, humidity, and mist irrigation. However, many greenhouses have few sensors inside their greenhouses and rely on a simple time clock and grower experience for mist timing. Commercially available sensors such as infra-red sensors for leaf temperature are being connected to a greenhouse control system at UF, to provide guidelines to growers on what sensors can be helpful. We are also helping commercial growers install sensors in mist zones. Climate data will also be used in a model of plant temperature and water loss to train growers on irrigation and climate control.

Shara Carolina Ortiz Carvajal, Master's student is researching prevention of rapid leaf collapse in Chrysanthemum. Cut flower chrysanthemum leaves can become chlorotic and necrotic during the first week in the vase. The cause of this phenomenon is currently unknown. We are evaluating pre-harvest and postharvest strategies to reduce the occurrence of symptoms. Green-flowering cultivars are the most susceptible, however many cultivars display symptoms. We have ruled out the possibility of bacteria as the cause, and we have also eliminated water relations as a causal factor.

Josselyn Gabriela Calidonio, M.S. Student at Clemson University, is researching effectiveness of different disease management agents for Botrytis in floriculture crops. Gray mold caused by Botrytis cinerea is a major disease that affects many floriculture crops. Weekly, preventative fungicide applications have been the main strategy for Botrytis management, but this lead to fungicide resistance development. The use of antagonistic fungi and bacteria has become popular and offers a sustainable disease management option. In our project, we are screening 20 compounds, such as biological control agents, plant nutrients, plant extracts, and systemic acquired inducers to observe their effectivity against gray mold in petunias, roses and gerbera daisies.

Melissa Muñoz Agudelo, Ph.D. Candidate at Clemson University, is researching management of Botrytis blight in roses. Roses represent a very important commodity in floriculture. Botrytis cinerea is a fungal pathogen that causes Botrytis blight and threatens rose profitability. Disease management relies often on fungicide applications; however, fungicide resistance development jeopardizes the efficacy and sustainability of this strategy. Prolonged periods of high humidity and moderate temperatures favor disease development, and these conditions are very often present in the greenhouses. These facts underscore the importance of developing alternative management strategies. Current research focuses on evaluating pre-and post-harvest applications of calcium in roses considering the role of calcium in enhancing the strength of the plant cell and mediating plant defense responses and secondary metabolites release against Botrytis cinerea.

Annika Kohler is a Research Technician at Michigan State University and is investigating the daily light integral (DLI) for indoor seedling production on common bedding plants such as dianthus, geranium, petunia, salvia, and snapdragon. Previous research has shown that a moderate DLI is sufficient to produce young plants indoors. However, technology and production practices continue to advance, including better light sources to maximize plant growth and increasing interest in utilizing LED lighting for indoor young plant production. We are evaluating effects of DLI on seedling production and subsequent performance after transplant to determine positive and negative attributes that can affect a grower’s schedule, such as flowering time and plant size.