Research from the Utah State University Crop Physiology Laboratory has produced decades of findings regarding hydroponic systems, controlled environment efficiency, and plant responses to environmental stress. These studies investigate critical factors such as nutrient bioavailability, the impact of lighting on canopy photosynthesis, and methods for detecting water stress through digital imaging.
Subheading: Nutrient Management and Soilless Media
Research conducted by the Utah State University Crop Physiology Laboratory has examined the complexities of nutrient delivery in soilless media. Studies have investigated how different iron chelates affect plant growth, including a 2022 study by Paul Kusuma and Bruce Bugbee regarding reduced chelate strength and iron bioavailability in monocots. In 2025, Christian Baker and Bruce Bugbee furthered this research by studying the effects of pH and iron chelate on the growth of basil and soybean within soilless media.
The laboratory has also addressed the technical challenges of liquid fertilizer systems. In 2007, Brendan Fatzinger and Bruce Bugbee identified that residue from Sequestrene 138 Fe EDDHA can clog filters in liquid fertilizer systems, leading them to seek alternatives for chelated iron. Additionally, research has explored the solubility of potassium silicate, noting that a pH of 11.3 enhances its solubility in liquid fertilizers, according to a study by Brendan Fatzinger and Bruce Bugbee.
Beyond chemical compositions, the lab has studied the physical properties of various growing substrates. This includes a 2005 study by Cody Alexander Tramp, Julie K. Chard, and Bruce Bugbee that optimized soilless media for alkaline irrigation water. Other investigations have compared the efficacy of coconut coir and sphagnum peat as components for soilless media for plant growth, as well as the respiratory quotient of peat, according to research by Jason Holman and Jake Nelson.
Subheading: Controlled Environment Efficiency
Advancements in controlled environment technology have significantly improved plant growth efficiency. In 2014, researchers at the Utah State University Crop Physiology Lab reported that lighting efficiency for plant growth had doubled over a six-year period. This research included studies on the return on investment for LED versus high-pressure sodium (HPS) fixtures, as well as the effects of retrofitting fluorescent lamp growth chambers with ceramic metal halide lamps.
Lighting quality and distribution also play a vital role in plant physiology. Research has examined how diffuse light panels can increase canopy light use efficiency, even though they may decrease light intensity and canopy photosynthesis in lettuce. Furthermore, studies have analyzed how different species respond to blue and green light, specifically looking at the interactions with photon flux, as well as the effects of blue light at high photosynthetic photon flux.
Subheading: Mitigating Environmental Failures
Research supported by NASA has addressed how to keep plants alive during prolonged periods of darkness, such as those caused by power outages in controlled environments. In a 2002 study, Julie K. Chard, Giridhar Akula, and Bruce Bugbee demonstrated that low light and cool temperatures can be used to maintain plants through 14.7 days of darkness, such as the duration spent on the dark side of the Moon.
This method relies on the fact that plant metabolism and growth are reduced in lower temperatures. By maintaining temperatures above the chilling threshold for a specific species, the energy requirements of the plant are reduced, allowing it to survive on less light. The research noted that plant growth resumes immediately once light is restored.
Subheading: Digital Detection of Plant Stress
Technological innovations have also enabled the non-destructive monitoring of plant health. In 2002, D. R. Pinnock, S. P. Klassen, and Bruce Bugbee established that digital cameras can be used to determine leaf expansion and relative growth rates.
This digital imaging technique is particularly valuable for the early detection of water stress. Because leaf expansion is reduced under mild water stress, taking digital images at daily or hourly intervals allows for the identification of these symptoms before they become visible to the naked eye.
Subheading: Long-Term Growth Dynamics
The lab's extensive research also covers the long-term effects of nutrient ratios on plant development. Studies have explored how different ratios of ammonium to nitrate (NH4+/NO3-) affect growth and nitrification in hydroponic cultures. These investigations have spanned several decades, including studies on wheat growth and nitrification in the late 1990s and early 2000s.
Subheading: Specialized Hydroponic Challenges
Specific challenges in deep-flow hydroponic culture have also been documented. Research by Noah Langenfeld, Saundra Rhodes, and Bruce Bugbee investigated copper toxicity at 8 μM (0.13 ppm) in tomato plants. Other studies have addressed the complexities of recirculating hydroponics and the management of various plant densities within these systems.
