Innovative strategies for greenhouse growth

Garrett Owen to present propagation and growth management sessions

By Madi Schafer, contributing writer

Garrett Owen, assistant professor and Extension specialist for sustainable greenhouse and nursery production systems at The Ohio State University in Columbus, Ohio, will present two sessions at the 2025 Michigan Greenhouse Growers EXPO: Advancing Woody Ornamental Propagation with Environmental and Cultural Strategies and Beyond the Spray: Ethephon Drenches as a New Option for Managing Growth in Annuals and Perennials.

Advancing Woody Ornamental Propagation with Environmental and Cultural Strategies

During his presentation, Owen will highlight recent research on woody ornamental propagation, focusing on the effects of the propagation environment and cultural practices. Offering practical insights for nursery propagation and production, attendees will learn how these factors influence rooting and growth responses across 10 species.

“We’re going to explore how we can leverage the greenhouse environmental condition, whether it’s light or root zone temperature and cultural practices such as foliar IBA sprays, to improve and enhance rooting uniformity,” Owen said.

Owen notes that light levels during propagation can impact rooting quality for woody ornamentals.

“We’re finding that foliar spray applications of IBA do reduce the timeline of rooting for woody ornamentals. Those concentrations of IBA are significantly higher, but if we exceed a species limit, we can see a detrimental effect,” Owen said. 

According to Owen, light levels during propagation can impact rooting quality, specifically for woody ornamentals.

“Light is significantly important during propagation. When we propagate annuals and perennials, we often provide supplemental lighting, whereas with woody ornamentals, in most cases, they are propagated during the summer. We’re finding that shading to reduce light intensities is helpful to improve the overall rooting quality of those cuttings,” Owen said. “Also, we’re finding that foliar spray applications of IBA do reduce the time of rooting for woody ornamentals. Those concentrations of IBA are higher than those used for annual bedding plants and herbaceous perennials.”

While this is ongoing research, Owen is open for comments, suggestions and questions during his session.

Advancing Woody Ornamental Propagation with Environmental and Cultural Strategies

Wednesday, Dec. 10, 2025

8:30 a.m. – 9:20 a.m.

Beyond the Spray: Ethephon Drenches as a New Option for Managing Growth in Annuals and Perennials

In this session, Owen explores the use of ethephon drenches as an innovative alternative to foliar sprays for managing growth in annual and perennial bedding plants. Attendees will learn how substrate drench timing, substrate composition and potential residual effects influence growth control and crop quality.

“Growers will learn about the responses of various annual and herbaceous perennial plants to increase concentrations of ethephon,” Owen said. “Growers will also learn when they should consider applying ethephon substrate drenches, the efficacy and influence of ethephon substrate drenches based on soilless substrate composition, and the residual effect of ethephon substrate.”

Overall, Owen looks forward to this year’s EXPO, connecting with familiar faces and networking with new growers in the industry. 

“I am most excited about being back in Grand Rapids and seeing all the growers,” Owen said. “It’s a great show that’s at the end of the year and gets everybody excited for the next growing season.”

Beyond the Spray: Ethephon Drenches as a New Option for Managing Growth in Annuals and Perennials

Wednesday, Dec. 10, 2025

1:30 p.m. to 2:20 p.m.

Renowned as one of the premier agricultural trade shows in North America, the Great Lakes Fruit, Vegetable and Farm Market EXPO and the Michigan Greenhouse Growers EXPO bring opportunities to connect, innovate and grow. Growers will connect with over 4,500 fruit, vegetable, farm market and greenhouse individuals and over 400 industry-leading companies. The EXPO will take place Dec. 9 to 11, 2025, at DeVos Place in Grand Rapids, Michigan.

To learn more about this year’s show and register, visit glexpo.com.