As president of the National Greenhouse Manufacturers Association, I want to convey our concerns over the impact of the COVID-19 virus, our prayers for continued heath, and our hope that we will return to normal soon. Our organization and members are all very proud to represent a great and growing industry. We continue to focus on greenhouse manufacturers, system component suppliers and educational representatives that contribute to and support the growth of greenhouses nationally.

Our organization is the collective voice of all of our members. We are not only the representatives to the International Building Code Committee but also promote best practices through education and networking at our annual meetings.

Usually, I convey the success of the NGMA spring conference, but 2020 is a special year, and our meeting has been postponed to the fall of 2020. This postponement is now an advantage to all of you. The NGMA will be hosting the annual meeting this fall, in Jacksonville, Florida, from October 11th to 13th. We encourage everyone who has an interest in the greenhouse market to attend. The annual meeting is filled with expert speakers, educational presentations and networking events, and we even throw in a bit of fun!

The NGMA codes and standards committee had a very successful year defending the greenhouse market and continuing to carve out awareness of the greenhouse structure in the building code. We can all agree that we want our environment to be healthy for us as well as our plants. The efforts to improve our planet’s environment are coming in many forms, one of which is the IECC energy code.

This year we lobbied and participated in the committee hearings to prevent proposed changes to increase restrictions in the energy code for greenhouses. After the fall hearings, we learned that we successfully defended our position and the proposal was rejected. Unfortunately, due to an extremely high level of influence and pressure from the energy conservation representatives, an unprecedented adoption of the proposal occurred without an opportunity to further debate our position. There are still a lot of details to be ironed out, and you can hear firsthand from the codes and standards committee at the fall NGMA annual meeting.

I want to personally thank the many volunteers who contribute to the success of NGMA. We have made progress with various initiatives, but the energy codes will continue to challenge to our industry. I encourage everyone to become an active member of the NGMA and I look forward to continuing to serve as president in 2020.

Tom Vezdos
General Manager
Rough Brothers, Inc.

While walking through 2 million square feet of production space at Skagit Horticulture in Mount Vernon, Washington, operations manager Corey Hill loves to see flats of plants pulled off to the side, undergoing various trials.

“That makes me happy because it means we’re trying to grow better and do something different,” he says. “I’m trying to provide that freedom to growers to be able to experiment, because we’re always looking for a better way to grow in the future.”

Committed to continuously enhancing the wholesale greenhouse’s operation, Hill encourages growers to look for opportunities to improve every day. Here’s how he does it.

Lean greenhouse

Hill started working at a retail greenhouse during high school to earn gas money, but “I had such an awesome experience, it made me not want to ever do anything else,” he says. After earning his botany degree, he worked at the greenhouse for a few more years until he met his wife there. They decided to move west and pursue horticulture careers in Washington, where she started working at Northwest Horticulture and he got a job at Skagit Gardens.

Hill spent about 10 years at Skagit Gardens before taking a head grower position at Van Wingerden Greenhouse. But then, a few years into that role, Northwest Horticulture ended up buying Skagit Gardens — merging to form Skagit Horticulture in 2017.

Who better to help align the newly joined teams at Skagit? “I was in a unique position where I knew people on both sides, so I had the opportunity to come back and help bridge them together,” Hill says.

Hill relied on his experience with lean manufacturing principles, which focus on minimizing waste while maximizing productivity. Rather than approaching any task, like transplanting, in terms of “our” way versus “their” way, Hill worked with the team to design more efficient processes together.

“We would sit down and talk through the process with the workers that were actually doing the job,” Hill says. “I can go in and tell them my way, but if it doesn’t end up being their idea, it won’t last long before they revert back to the old way. By building a whole new process, it allows the people doing the work to be the ones that decide how to do it.”

Free to experiment

After the merger, Hill stepped into the head grower role and then, in March 2018, he was promoted to operations manager. Now, he continues using lean principles every day to manage the operation.

“As operations manager, I do very little growing of plants,” he says. “I’m learning what all the other departments are doing and making sure my team stays in the loop so we can adjust what we’re doing. One of my main jobs is to remove barriers that are holding people back to keep the big picture in focus.”

Under the brand umbrella of Skagit Horticulture, the company caters to several distinct markets. It serves as the plug and liner division supplying other growers, while Skagit Gardens serves small independent garden centers, Northwest Horticulture serves large big-box retailers and a commercial agriculture division grows crops like grapes, hops, fruit and berries. Spanning four facilities in Washington and one in California, Skagit fills more than 2 million square feet of production space on 650 total acres.

Hill is based at the main location in Mount Vernon, Washington. Although he has “some oversight over the other locations, they’re currently running somewhat independently,” he says. In fact, he encourages his growing team to exercise independence regularly by setting up small trials to test regulators or other applications.

“We’re constantly trying new things,” he says. “If you were walking in our field, you’d stumble upon a randomized group of plants organized into a pre-emergent herbicide trial, where the growers grabbed one of everything and sprayed it with three different herbicides over the winter to see which one worked best and which plants liked it.”

Of course, the team stays in constant contact with Hill to make sure they’re trialing chemicals that are available and affordable, but other than that, “they’re completely independent,” Hill says. “That’s the funnest part of being a grower, is watching what kind of changes you can make and how it affects the crop.”

Change for the better

Although this spring has introduced unprecedented new challenges beyond the industry’s control, Hill says the mark of a successful grower is his ability to adapt and make changes in response to obstacles. The best growers keep driving change with the goal of producing better crops more efficiently.

“Most growers can’t make changes fast enough,” he says, “but you have to have the patience to make sure that change is sustainable.”

The author is a freelance writer and frequent contributor to Greenhouse Management magazine.

Garden mums are a popular floriculture crop, and they provide opportunity for summer production. It is common for garden mums to be grown outdoors, but since that environment can’t be controlled like the greenhouse, premature buds can form (Fig. 1), which can stop a crop from reaching its target height, resulting in unmarketable plants.

Causes of premature budding

Let’s review what controls flowering in chrysanthemums. Potted or florist chrysanthemum flowering is controlled by day length, induced by short days. However, garden mum flower induction can be influenced by both day length and temperature. Garden mums form flowers in response to short days, but temperature also influences flowers. Specifically, cool air temperatures (in the mid-60s or lower) can induce premature flowering in garden mums grown outdoors.

The effect of cool temperature on flowering poses challenges for producers growing their garden mums outdoors. Premature budding is most problematic for the earliest planted garden mums, such as large container sizes that require a longer production period, or for the earliest mum crops of the season. Whether it’s due to a large container size or an early sales date, the odds of experiencing cool night temperatures can move up the timeframe the crop is planted and placed outside. Cool temperatures can occur throughout the spring, and into June for northern growers.

Stress throughout the rest of the production cycle can also induce premature flower bud formation.

Temperature

The ability to mitigate temperature stress on garden mums varies widely depending on what environment the crop is grown in. As long as the target air temperature is correct and heating equipment is working properly, it is easy to avoid cold temperature stress in a controlled environment like a greenhouse. However, a large proportion of garden mums are grown outdoors, not in a greenhouse. There is little that can be done to protect mums from cold outdoor air temperatures. Short of building specialized structures for growing mums outdoors, think creatively about how you can use your existing space. If cold temperature-induce premature buds happen more often than not with your garden mum crops, see if there is any greenhouse space that may be available. Greenhouse space may be used to start the mums until the threat of cold temperatures has passed. Then they can be moved outside and finished. Alternatively, some garden mum crops are grown entirely in the greenhouse — not outdoors — mitigating risks of early-season cold stress.

Water and nutrition

Stressed garden mums are more prone to form premature buds, especially when exposed to cool temperatures. Keeping garden mums well-irrigated and -fertilized will help combat premature budding. Water and nutrition can be used to push growth that will cover the premature buds.

While growing on the dry side can help check growth and reduce disease pressure, it can also promote premature flower bud formation. Stressed plants can induce more easily than non-stressed plants. Therefore, keeping garden mums well-watered can help keep them vegetative. In addition to water, fertilizer can also help combat premature budding. Under-fed garden mums can be more prone to premature budding than plants that are well-fed. It is easier than you think to under-feed garden mums because they are heavy-feeding plants. Recommended nitrogen concentrations range from 250 to 300 ppm for constant liquid fertilization. One strategy that can be particularly useful for garden mums grown outdoors is to provide controlled-release fertilizer (CRF) at half the recommended rate, then combine with water-soluble fertilizer (WSF) at half the recommended rate. Additionally, since CRFs release more with warm temperatures, the unwanted spikes in EC from excessive nutrient release is avoided by using the half-rate of CRF.

These same recommendations for managing water and nutrition can be used even if premature buds form. By promoting vegetative growth through ample water and nutrition, vegetative growth can resume and grow over the premature buds. This will help “mask” the flowers and allow you to get your plants to their target finished size.

The basic control system for vents includes a sensor, environment control, contactor panel, vent controller and gearmotor that moves the vent arms.

Ethephon

Another useful tool to help avoid premature budding on garden mums is to apply ethephon, commonly available as Collate or Florel. These are ethylene-generating plant growth regulators, where the ethephon converts into ethylene after being applied to plants. One effect ethylene has on plants is that it, causes flower abortion prevents flower bud formation. So, by applying foliar sprays of ethephon to garden mums, premature buds are physiologically incapable of forming.

Ethephon applications can begin one-and-a-half to two weeks after cuttings are stuck for propagation. Applying up to 500 ppm ethephon work well for garden mums.. For pinched crops, wait a week or two after the pinch occurs. Be mindful of how much time is left to finish mums, as flowering can be delayed past the target flowering date if ethephon sprays continue too long. Adequate time needs to be allowed for plants to form flowers, and ethephon should not be applied with less than 6 to 8 weeks of production time left.

Take-home

Garden mums are an important crop for many growers, but growing outdoors presents challenges not experienced in conventional greenhouse environments. However, even though cool temperatures and stress pose the threat of inducing buds prematurely on mums, there are opportunities to modify the growing environment or culture to prevent premature flower formation.

Investing in energy curtains for the walls of a greenhouse can provide a rate of return on investment of 30% or more. With new greenhouses being built with a gutter height of 16 feet high or greater, the ratio of wall area to roof area is resulting in greater heat loss. For example, a 20,000-square-foot greenhouse with 16-foot height to the gutter will have about 30% more wall surface area than a standard house with 12-foot high walls.

Most of these new houses have one or more energy curtains to insulate the roof area, resulting in the heat loss through the walls being greater than through the roof. If the above house was glazed with double polycarbonate it would require about 428,000 BTU/hr for the uninsulated wall area and only 309,000 BTU/hr for the roof area with a double screen on a night with a 60° F temperature difference between inside and outside. If the walls were glass, the savings is considerably more.

The systems for insulating the walls have improved over the last few years. A system using a center motorized curtain roller is common, faster and more efficient, and stays straighter than rolling from the top only. The gearmotor unit with a large ratio rotates the shaft. It can be located on one end of the shaft for short greenhouses or in the center for long ones. Depending on weight and design, curtains as long a 450 feet can be rolled by one gearmotor. Safety torque and limit switches protect the motor.

There are two common types of curtain materials that will provide good energy savings. Both are polyolefins that have good strength properties needed for rolling and are fire retardant to meet the safety standards in the horticultural industry.

One is a clear fabric, L.S. Svensson — (Luxous 2845), that has good light transmission so that it can remain in place both day and night. It allows about 78% light transmission and has good light diffusing properties to allow sunlight to penetrate into the plant canopy. Tests show that it will have about 45% energy savings.

The second is a blackout material (L.S Svensson — Obscura 10070) that provides greater energy savings and also daylength control for crops such as poinsettias, mums and cannabis. It is laminated with white surfaces on both sides to reflect summer heat away from the greenhouse and reflect supplemental light back to the crop area. It blocks 99.9% of the light and provides 70% energy savings.

The typical cost of a motorized screen system is $2 to $5 per square foot, depending on the size of the installation, screen material used, number of obstructions that have to be worked around and ease of maneuvering man-lifts in the greenhouse. For a wall curtain with a transparent material that is not opened and closed fequently, a manual winch system may be all that is needed, saving about $1,000 for the gear motor and control.

Investing in energy curtains for the walls of a greenhouse can provide a rate of return on investment of 30% or more. With new greenhouses being built with a gutter height of 16 feet high or greater, the ratio of wall area to roof area is resulting in greater heat loss.

Based on the calculations from my energy audits, the payback for wall screens is between two and three-quarters and five years depending on the fuel price, location of the greenhouse, type of wall glazing and temperature at which the greenhouse is operated.

Wall curtains need to be installed to provide a tight seal all the way around the edges to prevent the cold air next to the wall from draining down and into the growing area. A fixed seal of polycarbonate sheets or fire resistant screen material is frequently installed to create the seal.

Incentive payments from the USDA’s Natural Resources Conservation Service or Environmental Quality Incentives Program, or a State Farm Energy program can help defray the installation costs. Low-interest Federal loans are also available for some of the remaining cost.