The U.S. Department of Agriculture’s National Institute of Food and Agriculture (USDA’s NIFA) has awarded a $300,000 grant to fund a research project focused on improving food safety for hydroponic lettuce production. The project will be led by the University of Arkansas’ Kristen Gibson, Ph.D., Director of the Arkansas Center for Food Safety and Arkansas Agricultural Experiment Station faculty member.

The project aims to meet the needs of the growing hydroponic lettuce industry, which, according to USDA, has more than doubled its production over a 5-year period, from 15.4 million pounds (lbs.) produced in 2015 to 36.4 million pounds in 2019.

Specifically, Dr. Gibson and her team will explore the food safety implications of growing hydroponic lettuce in soilless substrates, which could be a critical point for mitigating pests and pathogens. Soilless substrates like volcanic rock, coconut coir, sand, perlite, and vermiculite are used for the same purposes in controlled environment agriculture (CEA) as in traditional agriculture, which are to physically support crops and deliver oxygen, nutrients, and water to roots.

According to Dr. Gibson, soilless substrates are known to be a point at which pathogens could be introduced to plants, and the hydroponic greens industry is hungry for validated intervention strategies. Her research will address the control of both plant pathogens and foodborne pathogens known to sicken consumers.

The study will comprise two parts. First, in a controlled greenhouse environment, the researchers will observe a variety of substrates available on the market to determine which types facilitate the proliferation or persistence of pathogens and pests.

Next, the researchers will test different biopesticides, which are non-synthetic pest control substances, to find which varieties have the greatest efficacy in different substrates. Dr. Gibson intends to keep the feasibility of the different biopesticides for commercial-scale use at top-of-mind throughout her research.

The final objective of the project is to translate the findings from both parts of the study into best practices for growers. Dr. Gibson’s team will develop training materials delivered through extension activities, including workshops and training sessions with producers.

Co-principal investigators on the project include University of Arkansas’ Rupesh Kariyat, Ph.D., Associate Professor of Insect-Plant Interactions and Chemical Ecology in the Entomology and Plant Pathology Department, and Ryan Dickson, Ph.D., Assistant Professor of Greenhouse and CEA in the Horticulture Department. Drs. Gibson, Kariyat, and Dickson conduct research for the Arkansas Agricultural Experiment Station, the research arm of the University of Arkansas System Division of Agriculture.