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In Retrospect: A Look Back at the Past Year

Paul Pilon
Article ImageAfter an 18-year hiatus from actually growing plants, I had an incredible opportunity to get back to my passion for plants and accepted a Director of Growing position at Opel Growers in Hudsonville, Michigan, last December. I can’t believe a full year has passed by since I took on this opportunity. I guess the saying, “time flies when you’re having fun” is true.

Getting back into production was really a natural transition for me. Although growing plants on a day-to-day basis wasn’t what I did for the past 18 years, with my role as a horticultural consultant and working with various growers during this time, I kept up to date with production practices and perennial varieties. This proved to be invaluable, as I leaned on (relied on) these experiences to get me through my first year back in the trenches.

Pictured: Opel Growers’ overwintering houses. 

As with any year I’ve grown perennials in the past, there was a combination of things that went well and several areas that could use some improvement. While it’s important to take note of all the victories, I prefer to focus on the things that didn’t go as well as I’d hoped.

Here’s a look back at the past year, along with some comments I’m hoping will be useful for you in the upcoming growing season.

Things that went well

Improved crop uniformity with growth regulators. I consider myself one of the pioneers of using growth regulators on perennials, as I extensively researched and widely used them back at the turn of the century. Having this knowledge and experience was wonderful, but success with PGRs depends heavily on application timing, volumes applied and application frequency to get consistent results. It’s important to make PGRs a priority and not just a task you get to when you have time.

Lack of diseases. It was exciting to get through spring without any major disease outbreaks. Although I intended to implement preventative spray programs, I opted out and only applied insecticides preventatively. I attribute the lack of diseases with the highly effective humidity purge programs I put in place. I aimed to keep the humidity levels below 75% around the clock 24/7. The environmental controls were configured in such a manner that when humidity purges were necessary the heaters would turn off, the vents would open, then the vents would close allowing the temperature and humidity to stabilize, and then if more dehumidification was necessary, the heaters could run several minutes after the vents were closed (the heaters never ran when the vents were open).

Things to improve

Vernalization. I had several crops (echinacea and Phlox paniculata to name a couple) that literally sat there for weeks after planting them late last winter for early spring sales. These plantings were started with dormant liners. When they did wake up and begin to emerge, emergence was variable—some plants began to actively grow while others remained dormant. The plants that did wake up usually grew abnormally slower than expected. We experienced this variability on several of the liners we produced, as well as starting materials obtained from various suppliers.

The cause of the uneven emergence was due to incomplete vernalization, or in layman terms, the plants didn’t receive enough cold to overcome dormancy. Once most perennials go dormant, they need to receive about 1,000 hours of cold (temperatures below 4F (-15C) for them to break dormancy and begin to actively grow. This issue occurs most frequently with the first plantings of the season.

I’ve worked diligently to develop schedules and protocols to help eliminate this issue from occurring with our own starting materials. We’ll be heating some of the dormant starting materials from outside suppliers prior to transplanting them. This procedure is intended to break the dormancy prior to planting and should allow our finished crops to be more uniform.

Scouting. Like many greenhouse operations, there are times of the year where we’re time and people challenged. When this occurs, something must give and I’m as guilty as many growers are of letting some of the weekly activities slide. Scouting was one of those activities for me that got sacrificed when things got busy. Sure, the crops were still walked weekly; however, the amount of time spent in the crops looking closely for potential issues was significantly reduced.

I more than got by with this and didn’t have any major surprises; however, this isn’t how I want to manage crops. Getting by is not good enough. It only takes one problem that goes undetected to cause major headaches, crop damage and even crop losses. I’m planning to put expectations and processes in place this upcoming growing season to ensure that my growing team and myself can continue to properly care for the crops, even when things get a little chaotic in the spring.

Fertility. There were several periods of the past growing season that the injector was either not working or wasn’t functioning properly. Sometimes these issues were discovered very quickly, but there was more than one case when it wasn’t detected until the plants began to show deficiency symptoms, such as general chlorosis. This is really unacceptable. Improper fertility levels not only affect the appearance and quality of the plants, but they also affect how the plants grow and influences whether or not crops finish on time.

We’ve looked over our injector system to determine possible causes for its unreliability and made modifications where possible to alleviate these issues. Besides that, I wanted to emphasize the importance of the growers and water technicians knowing exactly what’s coming out of the hose as they’re watering their crops. Anyone who applies water to a crop should have access to a pH/EC meter. Checking the water before or as its being applied is the fastest way to detect and determine if the intended fertilizer solution is being applied or if there’s an issue with the injector. It literally takes just a few seconds to check the water. I’ll be emphasizing these practices with my team in the upcoming growing season.

These are just a few of the good and not-so-good things I recall. I’ll obviously continue with the good practices, but will be more focused on the areas that didn’t go as well as they could have. I encourage you to learn from my mistakes and analyze your own practices to make 2023 the best year ever. GT

Paul Pilon is editor-at-large of the Perennial Pulse e-newsletter and Director of Growing at Opel Growers in Hudsonville, Michigan. He can be reached at

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