Snow Loads: Holding The Winter Weight

A brutal winter can be a real wake-up call for growers. Forcing you to ask questions: Are my greenhouse structures up to par? Are they strong enough to withstand heavy snow from a late and unexpected storm while we’re in the middle of production?

The questions are legitimate ones, and industry veterans provide some answers. They explain how a little practicality, heat and attentiveness can go a long way – and may even save the season for your operation.

Snow Removal

Along with keeping a close eye on the local and national weather reports, Jaderloon’s Neil Devaney advises removing all exterior shade cloth before anything else.

“The snow will grab that cloth a lot more and hold,” he says. “If that happens, it won’t go anywhere and just turn into ice.”

Once the snow starts coming down, Devaney says long-handled brooms and PVC pipes are excellent for manually working the snow down and off of a structure, but be sure to work in teams.

“What you don’t want to do is have a person walk down and clean off just one side,” he says. “You want a person on each side – working at the same time. If there’s a lot of snow and you clean off one side, it might just shift the structure.”

When dealing with heavy, wet snows and snow-loaded greenhouses, Devaney advises against walking inside the structure until some of the snow and weight have been removed from the roof.

“There’s not a meter on there that reads, ‘Hey I’m getting ready to fall,’” he says. “It can be a domino effect if one part of the structure collapses, because that places a ton of weight and stress on the remaining bolts and supports.”

For growers with ground-to-ground structures, two-by-fours are an easy way to provide additional support to the frame, says Burt Moore, Atlas Greenhouse Systems engineering manager. Having these posts notched, pre-fit and ready for severe weather will do a lot of good, he says. “Place these support columns down the center of the buildings during the winter months, every 10 or 12 feet. When the weather warms up again, they can be easily taken down and stored.”

Sans Penny Pinching

At Jaderloon, Devaney has experienced many growers trying to get the least amount of greenhouse for the least amount of money. “I tell people all the time: The frame, which is your strength, is about 20 to 25 percent of the overall greenhouse project costs, and if you increase that frame cost by 10 percent, you get a much stronger greenhouse and you’re not increasing the overall project cost by very much.”

Steve Mercer, manager at Preston Greenhouse in Louisville, Ky., completely agrees with Devaney’s advice. In the last 30 years at Preston Greenhouse, Mercer has never experienced a collapsed structure, even during winters that have loaded his greenhouses with 3 feet of wet snow.

“To start with, we try to overbuild our houses,” Mercer says. “We try to construct them by using vendors who know how to build structures for northern climates. And even though some people in our area would build a southern-style greenhouse, we like to build to northern specs.” One example of that is column spacing. In gutter-connect housing, Mercer says some growers will space their support columns 12 feet apart, while Preston Greenhouse works on 9 feet of spacing.

“We build for worse-case scenarios,” he says. “We never want to put ourselves in a position where we have a house caving in on a crop. Not only do you have to experience the labor to tear down the damaged house and take the time to rebuild it in the middle of a production cycle, you’re also at risk of losing the crop. I don’t see how anybody can justify being pennywise and pound foolish in this situation.”

Mercer notes that Preston has one weaker house that is coming down this year. “When we build it back, it’s going to be built a whole lot stronger.”

Heating Up

Keeping on top of snow removal is important because of its ability to insulate and also block light. In the same breath, Atlas’ Burt Moore says keep the structure well heated, especially before the snow hits.

“We typically recommend to keep heating at 50 degrees Fahrenheit at 3 feet above the finished floor,” Moore says. “Naturally, heat rises, and that means if you can keep it at 50 degrees at that level, at head-level it’ll be 60 degrees, and up in the top it’ll be in the 70s.”

Devaney adds that increasing a greenhouse’s temperature costs money, but he asks what’s more expensive: Running heat for six hours or replacing a structure?

Moore and Devaney agree, the main goal in a snowy situation is maximum heat loss. Growers should pull back all interior shade systems, and those with double-poly houses need to turn off the inflation system to increase heat loss.

“We turn the heat up, bringing the temperatures up to 70,” Mercer adds. “Do you really want to bet the company on a weaker house and being in the middle of a production cycle and lose the house and the crop, too, and not be in business when the customers start coming around? That’s a pretty big bet.” 

Leave a Reply

More From Structures...

February 15, 2017

Growers Planning to Invest in Structures in 2017

Data from this year’s Greenhouse Grower State of the Industry survey indicates that growers are planning to make major investments in structures and facility upgrades this year.

Read More
NVAC Greenhouse prototype

February 15, 2017

New Greenhouse Cooling System in Development for Hot-Climate Regions

Researchers at McGill University in Quebec have developed an alternative evaporative cooling solution for greenhouses in warm climates, and are now seeking commercial partners.

Read More

February 15, 2017

Registration Open for NGMA Spring Meeting

The annual gathering of the National Greenhouse Manufacturers Association will feature a look at green industry trends, emerging market opportunities, and more.

Read More
Latest Stories

February 15, 2017

Growers Planning to Invest in Structures in 2017

Data from this year’s Greenhouse Grower State of the Industry survey indicates that growers are planning to make major investments in structures and facility upgrades this year.

Read More
NVAC Greenhouse prototype

February 15, 2017

New Greenhouse Cooling System in Development for Hot-Cl…

Researchers at McGill University in Quebec have developed an alternative evaporative cooling solution for greenhouses in warm climates, and are now seeking commercial partners.

Read More

February 15, 2017

Registration Open for NGMA Spring Meeting

The annual gathering of the National Greenhouse Manufacturers Association will feature a look at green industry trends, emerging market opportunities, and more.

Read More
EFTE Film

January 18, 2017

Looking at Glass or Polyethylene for Your New Structure…

Ethylene Tetrafluoroethylene, also known as EFTE, is a fluorine-based material that looks like a standard polyethylene greenhouse film but offers high light transmittance.

Read More
Nadia Sabeh, CEAC

January 18, 2017

Upcoming Seminars to Focus on Managing the Greenhouse E…

The seminars, which will also be accessible online, are presented by the University of Arizona’s Controlled Environment Agriculture Center.

Read More

November 16, 2016

Stay Up To Date On Greenhouse Structures And Materials

eGro, an online resource for greenhouse growers, features a series of video lectures and tutorials on a wide variety of topics, including greenhouse structures and terminology, heating and cooling, and more.

Read More
Dual Atrium Greenhouse (Nexus)

October 12, 2016

Gibraltar Industries Acquires Nexus Corporation

The building manufacturer and distributor strengthens its position in the U.S. greenhouse market, complementing its RBI greenhouse company with the aquisition of Nexus Corp.

Read More
Gotham Greens Atrium Style Greenhouse Chicago

September 14, 2016

How An Energy Audit Of Your Greenhouse Can Save You Mon…

Is your greenhouse utility bill getting you down? Consider an energy audit to evaluate potential energy savings.

Read More
JGS Structure at Vineland

September 14, 2016

Take A Virtual Tour Of Canada’s Vineland Greenhouse Tec…

The one-of-a-kind research greenhouse project was completed by JGS Limited and features 40,000 square feet of horticultural research space.

Read More
Stuppy Greenhouse Manufacturing's Rainbow Super Structure

September 14, 2016

NGMA Contributes Revisions And Updates To Building Code…

The revisions cover the definition of a greenhouse, improved efficiencies in making greenhouse code changes, and more.

Read More
GrowSpan Light Deprivation Greenhouse

August 25, 2016

New Light Deprivation Greenhouses Help With Light Manag…

The GrowSpan light deprivation greenhouse from Growers Supply is outfitted with a blackout system that provides growers with control over the light cycle.

Read More
Cannabis Structure

August 23, 2016

5 Factors To Consider In Your Cannabis Structure

Along with the size and specs of your greenhouse, it's also important to focus on ventilation, light deprivation, benching, irrigation, and odor control.

Read More
Nexus Dual Atrium at Lucas Greenhouses

August 15, 2016

6 Ways Greenhouse Suppliers Are Partnering With Produce…

Greenhouse and equipment manufacturers share how they work with growers to provide customized solutions.

Read More
Cannabis Structure

July 28, 2016

How To Maximize The Efficiency Of Your Cannabis Structu…

The up-front costs of creating your cannabis facility may be high, but at least one expert says making the investment now will be well worth it down the road.

Read More
Floral Greenhouse at Vineland Research Centre

July 20, 2016

Research And Commercialization Unite At The New Vinelan…

The new, pre-scale commercial greenhouse facility at Vineland Research and Innovation Centre in Vineland Station, ON, will help accelerate the commercialization of innovative technologies and products coming out of research.

Read More
Geranium Injured By Ethylene

July 20, 2016

How To Prevent Greenhouse Heating Leaks

Ethylene from malfunctioning greenhouse heaters can lead to crop injury, while carbon monoxide can lead to worker illness. Know the symptoms and how to check greenhouse heaters to avoid these concerns.

Read More
GrowSpan Screen cap

July 18, 2016

Growers Supply Launches GrowSpan Website With New Conte…

The GrowSpan website will encompass the brand’s entire greenhouse structure line, and allows growers to quickly browse GrowSpan’s product offerings based on structure type.

Read More
Lisa Ruggiers, National Greenhouse Manufacturers Association

June 15, 2016

Meet The New Executive Director Of The National Greenho…

Lisa Ruggiers has been active in NGMA for several years, and will work closely with the group’s officers and board of directors.

Read More