WOOSTER, Ohio –Plant response based environmental control is the focus of The Ohio State University’s annual greenhouse management workshop. It will take place Jan. 27-29 and will be a virtual conference because of the pandemic.

Growing ornamental and food crops in a controlled environment requires careful monitoring of a plant’s physical and physiological aspects. This three-day workshop will address the fundamentals of greenhouse management, from understanding water and nutrient needs to disease and pest control, according to the OSU website.

“Typically when we adjust the temperature in the greenhouse we use indirect controls because all of the plant ecological processes are controlled in the plant,” said Peter Ling, OSU faculty and Ohio Extension specialist in greenhouse engineering. “It is more direct if we can look at the plant directly and adjust the microenvironment they are experiencing to be more effective. It’s like if we go to a doctor they put a thermometer into our mouth to measure our temperature directly instead of putting a thermometer three feet above our head. Observe the plant directly.”

The plant growth, or to be more specific the efficiency of photosynthesis, is affected by the leaf temperature, Ling said. Through transpiration, the leaf temperature can drop lower than the surrounding air. When the sun is shining on the leaves it is going to be warmer than the surrounding air. So the air temperature is not an accurate indicator of what the plant is experiencing. Thermal tools are commercially available for assessing leaf temperature.

Wednesday’s workshop topics explore the fundamentals of crop production in a controlled environment. On Thursday, attendees will learn about plant monitoring tools. Friday’s subjects include commercial tools and research updates.

On Thursday, Ling, a workshop organizer and presenter, will talk about Just in Time irrigation.

“If you have plants in the house the number one reason you kill a plant is that you water too much,” Ling explained. “The second reason is you water not enough. It is tricky to water plants.”

In a production environment, if a grower overwaters, the water, which probably contains fertilizer and other chemicals, leaches through the pot and into the environment.

“That could be an issue as far as environmental sustainability,” Ling explained. “So what we try to do is see when is the best time to water plants and also how much to water it. Because even if we know when to water it, if we overwater, the leachate is contaminating the environment.

“We can determine that and how much and how to water. If you pour water on top you’re going to lose probably 90 percent of the water. That’s not a good way to do it. Plants have different shapes and sizes and different growth stages. Just in Time watering is knowing when to water and how much to water.”

Whether growers are interested in small container growing, vertical farming or greenhouse growing, it all comes under the same umbrella, Ling said.

Continuing education credits have been requested for Ohio Pesticide Credit Recertification, Michigan Pesticide Certification, Indiana State Chemist Certification and Pennsylvania Pesticide Recertification. 

To register, go to fabe.osu.edu, scroll down to the events calendar and click on the workshop link. For information, contact Mary Wicks, OARDC/OSU: email wicks.14@osu.edu or by phone, 330-202-3533.