New advances in environmental control technology are giving growers more tools to monitor plant conditions in the greenhouse.

In the future, there will be sensors that can signal when a plant is thirsty, when it needs more nutrition, when it is undergoing an insect infestation or is a little under the weather. We may not be at this point yet, but there is high-tech gadgetry available that can tell us a lot about the environmental conditions in a greenhouse and even around the immediate vicinity of the plant.

Regardless of how sophisticated these environmental control (EC) systems are, it’s up to the grower to be able to read and interpret the data they produce and use that data to advance the health of the plant. After all, the overall goal is to grow the highest-quality crop with the lowest number of inputs, such as fertilizers and insecticides, while also using the least labor possible.

“Consider that the genetic potential of any seed — or cutting — can only be achieved if the proper environment consisting of [temperature, humidity, light, CO2, water and nutrients] is provided at the right levels and proportions at the right time to exhibit that plant’s potential,” says Dr. Gene A. Giacomelli, professor of agricultural and biosystems engineering at the University of Arizona and director of its Controlled Environment Agriculture Center (CEAC).

Getting up close

Typically, environment controls measure the conditions in the greenhouse itself, but advanced environmental controls now have the capability to measure environmental conditions close to the canopy of the plant, giving the grower more accurate readings than just a few years ago, Giacomelli says.

“Sometimes environmental controls have sensors away from the plant. You have potted plants, bedding plants or lettuce growing on the ground or even the tables, and you have sensors a couple feet above it,” Giacomelli explains. “It’s measuring the greenhouse air temperature but not really measuring the temperature, light and CO2 near the plant.”

Giacomelli says environmental control technology offers “better crop response [to environmental factors], ability to save data for future evaluation and forewarning of a problem.” He adds that data collection can also be centralized so it can be evaluated back at the office or remotely. Smartphone apps are also being used to keep tabs on plants in the greenhouse, providing a “fail-safe” solution for a grower’s investment of time and money.

Learning to read and interpret data

Still, environmental control systems are only as good as the people who can read, interpret and make use of the data.

“In order to correctly read and effectively interpret and use the data timely and resourcefully, the growers must have certain skill sets,” says Murat Kacira, professor of agricultural and biosystems engineering at the University of Arizona. Kacira also works at the CEAC.

He says growers must first understand the biology of the plant and recognize the importance and “effect/interaction” of the environmental variables for which the data is being collected, the crop quality and yield, and the environmental control processes and resources used.

Both researchers agree that there is a need to train growers to read and interpret the data that is produced with environmental controls. Kacira says critical thinking skills are necessary to recognize and appreciate the complexity of the data being collected and identify potential sources for error in the system that can result in inaccurate data collection. Errors in data collection are most likely to occur with the sensors, says Giacomelli, who calls for an annual checkup on the sensors and other equipment in the greenhouse to ensure everything is calibrated correctly and working properly.

In addition, Kacira says computer skills and some level of computational literacy are needed to be able to access the data in the databases of the environmental control system. Math skills are needed to collect and analyze the data, and some understanding of chemistry is helpful for understanding fertilization. Lastly, communication skills are paramount to be able to effectively exchange data, results and other growing information.

The future of controlled environment agriculture

Giacomelli says, in the future, there will be sensors to monitor what is going on in the plant itself. These sensors will tell the grower, in real-time via computer, how well the plant is responding in its current environment, giving the grower more direct knowledge of the plant itself, because that’s what they really want to control.

“We don’t really want to control the greenhouse — we have to right now — because if we control the greenhouse, we learn that the plant will grow and respond to this temperature in the greenhouse, or this light level in the greenhouse,” Giacomelli says. “But what if we could listen to the plant with these new sensors and have the plant tell us its current state of existence? [For example] ‘The sun is out, I have plenty of water and nutrients and I’m growing.’” He added that if the grower was able to use sensors for this, they could adjust the plant’s environment with a little more precision.

That day may not be that far away. Currently, researchers at Iowa State University are introducing an adhesive graphene sensor that can be attached to a plant to monitor water vapor. The sensor, which can be sized down to millimeters, records how much and how fast a plant can consume water. They say it’s a “tiny, low-cost answer for a major issue” in agriculture.

Initially, the sensor developed at Iowa State will be used by breeders to measure drought tolerance in different crop varieties. The researchers think the major use will be in outdoor agriculture, but one could easily see how it could be used in covered growing situations and eventually provide other readings, such as the amount of light it is receiving, CO2, etc.

Knowledge is power

As the old saying goes, “knowledge is power.” and environmental controls are the backbone to the future of controlled environment agriculture (CEA). Growers need to produce plants in the most efficient and sustainable way as the population of the world increases and we turn more toward CEA to produce food closer to markets and to cope with erratic climatic events.

“In the future, we will need all of the information and experiences we have from the past, but it will be supplemented with more information in immediate time that is directly received from the plant to indicate its in good condition or that it’s heading into a state of stress,” Giacomelli says. “You will use this information to reduce the stress and enhance the plant growth and quality. You will ultimately be able to automate even more to reduce production labor costs and to improve crop quality.”

Kacira expects to see further integration of precision horticulture system applications with the use of computer vision, robotics, artificial intelligence and the Internet of Things, resulting in the “integration and collaboration of the mechanical, digital, biological and human world in agricultural production systems.”

Environmental sensors may soon be able to give growers real-time data on how their plants are doing.

“There is growing interest in developing smart computer vision and artificial intelligence-based crop growth and health diagnostics and pest infestation monitoring and control systems,” Kacira says.

Giacomelli predicts that we’ll need to use fewer resources and less waste to produce food. He thinks there will also be more crops grown indoors, including high-nutrition greens, plants with medicinal properties, such as cannabis, and plants that require less water or fertilizer to grow effectively.

He predicts these crops will also be grown where growing wasn’t feasible on Earth and beyond.

“There has been no more exciting time to be a greenhouse CEA grower than right now,” Giacomelli says.

This article was originally published in the March 2018 issue of Greenhouse Management.

Neil is a horticulturist and freelance writer and copywriter for the green industry.