Controlled environment agriculture (CEA) is a broad term, usually defining the production of specialty crops, edible, medicinal, and ornamental, in indoor systems – frequently in soil-free systems – with the technology to control the environment, such as greenhouses and vertical farms/plant factories.

UGA has a solid horticulture program with talented faculty and students and a strong reputation in LED lighting in CEA at the Horticultural Physiology Lab. The existing infrastructure, faculty, staff, leadership, and focus on active learning brought me to this remarkable institution to establish a powerhouse for research and education in CEA at UGA.

For many years, we have used classic methods for plant production in the field and the greenhouse. Our lab will challenge these assumptions using new technologies on precision irrigation (different hydroponics systems and water management), plant nutrition (nutrient management and sap analysis), and cropping systems (substrates, biostimulants, and high-throughput phenotyping in greenhouses, and calcium accumulation in lettuce and spinach under increasing air flows, biopharmaceuticals, and biofortificants in vertical farms) for various horticultural specialty crops.

I am studying plant responses to different production factors and developing methodologies to maximize plant growth rate, development, morphology, physiology and ultimately improve horticultural crop yield, quality, and profitability.

Dr. Ferrarezi taking photosynthesis measurements using a PP Systems Ciras-3.

Precision irrigation

We are investigating the best hydroponics systems and water management strategies in hydroponics to maintain adequate plant growth in CEA.

Our lab has extensive experience with soil moisture sensors, ebb-and-flow subirrigation, and irrigation automation using low-cost open-source platforms (Arduino and Raspberry Pi).

Plant nutrition

We want to start finding the best approach to maintain an adequate fertilizer solution in large-scale systems and reduce – and why not eliminate – solution waste to minimize the potential for environmental contamination. Another field that I want to investigate is the fertilizer recipe for multiple crops, sources, timing, supplemental nutrient application, and biostimulants.

Sap Analysis

Plant sap analysis is a powerful option for determining nutrient status. The sap is defined as the liquid portion extracted from the xylem and phloem, which are the conductive tissues in the plant. The nutrients in the sap are readily available for the development of the plant. Therefore, sap analysis is compared to a tree “blood test”.

An early determination of the plant nutrient status is beneficial for managing fertilization because plant sap analysis relies on real-time information. Plant mineral levels, nutritional deficiencies, and excesses could be determined before they cause any damage to plant development and, consequently, reproductive stages. Different sap analysis methods are available for vegetable crops and include comparing the sap of new vs. old leaves. The purpose of this comparison is to assess nutrient mobility between new and old growth. This comparison also makes it possible to indirectly infer nutrient uptake and predict interactions such as synergisms and antagonisms.

There is plenty of knowledge for sap analysis in vegetables but not much for CEA. Moreover, the sap extraction and result interpretation are bottlenecks since they vary from crop to crop. Sap analysis is becoming a hot topic in CEA because some producers started using it as an extra tool to guide quick fertilization decisions. However, there is a need to establish the sampling timing, tissue age, sample size, sampling frequency, extraction and analysis methods, and sufficiency ranges. We also need to interpret results for different short-term crops with tender tissue and compare the results with leaf nutrient concentration since that is the standard.

Cropping systems

Sound cropping systems are based on new technologies and reliable experimental data. For this reason, the Ferrarezi lab is covering several aspects of horticulture to improve CEA production and better quantify the impact of the environment to plant performance.

NFT hydroponics system using on a study about the effect of fertilzier solution temperatures on dissolved oxygen concentration.

Our lab is currently researching substrates, biostimulants, and high-throughput phenotyping in greenhouses, effect of temperature on dissolved oxygen, and calcium accumulation in lettuce and spinach under increasing air flows, biopharmaceuticals, and biofortificants in vertical farms. Exciting stuff!

Lettuce plants with biodegradable containers (left) and plastic net cups (right)
Lettuce roots grown with biodegradable containers (left) and plastic net cups (right)
Substrate comparison for leafy green production in deep water culture hydroponics