Building codes and greenhouses

Supplement - State of the Industry Report

The National Greenhouse Manufacturers Association is focused on writing standards specific to greenhouses and assisting the proper authorities to ensure these structures are understood and treated correctly.

July 26, 2010
Craig Humphrey

Growers should expect issues related to sustainability and energy efficiency will have an impact on some of their greenhouse-related projects.Over the past several years there has been a near universal adoption of some version of the International Building Code (IBC) in all states. The governing codes have actually changed very little, but the enforcement has increased along with the issues that building officials may want to address. Previously, growers may have only had to be concerned about snow and/or wind loads, but now other issues may be addressed including coverings, building sizes and fire-related concerns.

For previous greenhouse projects you may not have had to obtain a building permit. Don’t be surprised if a permit is now required. Municipalities and other government entities have had to deal with budget shortfalls due to the economy. One way they have found to generate additional revenue is through the enforcement of building codes that previously had exempted construction projects like greenhouses.

Permits and code changes may require that a grower construct a professionally engineered structure where previously a non-load rated greenhouse may have been allowed to be built. Make sure you and the local building official are clear as to the purpose of your expansion project to ensure the proper rules are being applied.

Building codes dictate, for example, what size structure is allowed along with the type of covering that can be installed. These codes govern fire safety issues and fire sprinkler requirements. There will be specific requirements for snow and wind loads for your particular location. Be aware that if it has been some time since you built a greenhouse, these loads may have changed and your old structures may not be considered sturdy enough to withstand current loads.

Previous building codes can be altered due to recent events that caused structure failures or exposed deficiencies in the code. An example of this is the snow storms that occurred this past winter along the eastern United States. The weight of the snow caused many greenhouses to fail resulting in collapsed and damaged structures.

Many of these damaged structures were manufactured by companies unfamiliar with U.S. weather conditions and were sold without considering U.S. building codes or the NGMA structural standards. The failure of these non load-rated structures could hurt the U.S. greenhouse industry if the loads are increased without proper investigation and comparison to the performance of NGMA-designed structures. The failure of these structures could lead to an eventual increase in design loads.

Building code benefits
Greenhouse design can also benefit from building code language. An example is the reduction in the snow loads for greenhouses due to the heating of structures. Building code authors understand that greenhouses are covered with glazing materials that allow heat to rise and melt the snow that falls on the roofs, thereby preventing the snow from accumulating. There are restrictions on heat and covering types needed for this thermal factor reduction, but many greenhouses can qualify. A less insulated greenhouse roof compared to normal building construction may cost more money to heat, but it can result in savings on the structure design. The building codes and the NGMA standards reference this thermal factor reduction.

If the greenhouse manufacturer uses the thermal factor reduction in the design of your structure, the heat needs to be turned on prior to a snow storm to raise the temperature in the house. You assume the responsibility to protect your investment as the reduced design may incur some structural damage during a storm. Check with your insurance carrier to learn its requirements related to design and operation during storms. If you are unsure whether a greenhouse manufacturer is using this reduction, you can request that the company has a professional engineer stamp and certify the design. NGMA has a certification form available for an easy comparison.

Production greenhouses that restrict public access benefit from building code language by receiving a load reduction due to a lower risk to life safety. Building codes don’t always have a negative impact on greenhouse design. Professional engineers and architects can help you determine the impact the codes have on the structure you are interested in building.

Sustainable construction
The latest topics in construction projects are focusing more on issues related to sustainability and energy efficiency. Expect some of these same issues to have an impact on some of your greenhouse-related projects. The federal government, along with an increasing number of states, are putting more pressure on building departments to have new construction conform to energy codes that reduce the dependence on fossil fuels. Most states will be implementing energy codes that will influence building materials and systems.

The differences between commercial production and garden center greenhouses can be drastic depending on the particular location and weather. Commercial greenhouses are usually exempt from conforming to energy code requirements due to their agricultural use. Retail garden centers fall into a different category and their requirements can be significantly different. Many times they must meet the same building requirements as other types of commercial construction.

The need for a design professional who has experience dealing with energy codes is a must. Greenhouse manufacturers must find ways to increase energy efficiency of their structures to meet the expected changes in code requirements.

NGMA is focused on writing standards specific to greenhouses and assisting the proper authorities to ensure these structures are understood and treated in the correct manner.

Craig Humphrey is vice president engineering, Nexus Corp. (800) 228-9639; www.nexuscorp.com. He is chairman of the NGMA Codes and Standards Committee.

Simplifying sales

Departments - Outlook

I expect most people attending the California Spring Trials experience to some degree that “kid in a candy store” feeling.

July 26, 2010
David Kuack

David Kuack

I expect most people attending the California Spring Trials experience to some degree that “kid in a candy store” feeling. Even being a 20+ year trial veteran, I still look forward to seeing what’s new in regards to plant introductions. Prior to arriving in California I wonder if there will be at least one new variety that will cause me to say “Wow, that plant should get consumers excited.”

The other questions I usually ask myself after a week of making nearly 20 stops to view products from about 30 plant companies are, does the industry really need this many new plants every year and how many are actually going to make it onto the retail shelf?

In a recent article in the Globe and Mail, the Toronto newspaper reported that Walmart Canada Corp. decided to overhaul its peanut butter offerings. In order to make room for additional “spread” products, the retailer reduced the number of peanut butter lines it carried from five to three. The result was that peanut butter sales actually went up. The reduction in offerings made it easier for consumers to choose and so more peanut butter was sold.

I wonder the same thing about consumers and their decision to buy plants. Are they so overwhelmed by the selection that they just give up and walk out of a garden center without making a plant purchase? I expect they may make a lawn and garden purchase (i.e., fertilizer, chemicals, garden tools, etc.), but is the plant selection too extensive for them to make an “intelligent” buy? Duncan Mac Naughton, chief merchandising officer at Walmart in Mississauga, Ontario, told the newspaper that too much variety can overwhelm consumers resulting in them not buying.

Keeping it simple
A 2007 study by consulting firm Bain & Co. found that reducing product offerings reduces a company’s operating complexity. The study indicated this simplification can help companies increase revenues by 5-40 percent while cutting costs by 10-35 percent. The study indicates elimination of complexity makes it easier for companies to identify fast sellers and improve product and service quality. Companies that had the lowest complexity grew 1.7 times faster than the average competitor, according to the Bain analysis.

One company at this year’s Spring Trials made simplification a part of its message. Suntory Flowers, which downsized its display, promoted the fact that it made it easier for growers to choose plants by reducing the number of varieties it offers.

I’m not expecting there to be any major changes in the number of new varieties introduced during the trials. Some people feel that new varieties are one of the major drivers of our industry. But it’s the consumer who’s the ultimate driver. And if a plant doesn’t meet her performance standards once she buys it, the life expectancy of that variety is going to be shortlived.

Alstroemeria

Departments - Culture

A how-to production guide

July 26, 2010
GMPro

Fides’ Inticancha alstroemeria series has been bred specifically for pot plant use. The genetically dwarf, free-flowering plants are available in nine varieties. One 2-inch rhizome liner can fill an 8- to 12-inch pot. Plants should not be grown in smaller pots because the rhizomes will not have adequate space to develop.

The liners should be planted into a well-drained growing medium (i.e. 60 percent peat and 40 percent coco fiber) with a pH of 5.5 and electrical conductivity of 1.0.

Liners planted in the fall should receive a minimum 24-hour average temperature of 54°F-57°F. Keep the humidity below 85 percent to prevent Botrytis.

The natural light levels in North America are high enough so that lighting is not a critical issue. The production time for the plants is about 16-20 weeks. Fall planting production takes longer than spring plantings because of the seasonal lower light levels.

Inticancha Sunday and Sunlight have a more vigorous habit and grow larger than the other varieties. These two are better suited for outdoor production or in areas like the southern United States that have higher light levels. The other varieties can be produced both indoor or outdoors.

Moisten the medium thoroughly, but do not overwater to avoid root rot diseases. Fertilize with a standard soluble fertilizer with trace elements (i.e., 14-14-28). Maintain an electrical conductivity level of 2.0. This level can be gradually increased to 2.5 later in the production cycle to stimulate flower initiation.

Plants can be moved to final spacing six to eight weeks after planting. Plants grown too close won’t achieve a rounded, compact shape. Plants should not require any plant growth regulators.

Plants don’t need to be pinched. Growers should remove blind shoots, which causes the plants to induce flowers in new shoots. Plants can be sold with a minimum of two to three open flower rosettes.
Insect pests can include slugs, thrips, aphids, spider mites and whitefly.

For more: Fides North America, (805) 525 7125; www.fidesnorthamerica.com

1. Inticancha White Pink Heart, 2. Inticancha Sunlight, 3. Inticancha Sunday, 4. Inticancha Creamy Dark Pink, 5. Inticancha Red, 6. Inticancha White Pink Blush, 7. Inticancha Dark Purple.

Choosing new varieties

Features - Marketplace

Years of experience have led Jon Pinkus of Nortex Wholesale Nursery in Dallas to determine local trials are the best way to find new varieties that work in the extreme Texas climate.

July 26, 2010
Jennifer McLean

Years of experience have led Jon Pinkus of Nortex Wholesale Nursery in Dallas to determine local trials are the best way to find new varieties that work in the extreme Texas climate. He also depends on information gleaned at the OFA Short Course, from breeding companies and distributors who attend other trials, as well as industry publications.

He noted the Dallas Arboretum Trials were a good source for finding new plants. Nortex also does its own trialing.

Recently, Pinkus has seen a big improvement in pentas and found gerbera playing a much bigger role in the marketplace. His biggest surprise has been how much attention calibrachoa receives in his region.

“They don’t take the heat well, but from a retail perspective, consumers see how good they look in the garden center, take them home and discover they’re watering them two or three times a day to keep them looking fresh,” he said. But they’ve been good sellers.

Other products that have worked well are zinnias and begonias, especially Dragon Wing.

The company’s retail garden center has experienced an increased interest in edibles, including vegetable and a strong surge for herbs. The company recently installed an organic display garden with raised beds and offers classes to promote gardening and local growing.

For more: Nortex Wholesale Nursery, (972) 442-5451; www.nortexgrows.com

Tried-and-true
Fred Hammerle with Juniper Hill in Cutchogue, N.Y., is of the firm opinion tried-and-true plants are the ones to produce. But he’s not adverse to trying new plants. At least nine times a year, he’s visited by various breeding company reps who give him in-depth presentations. He uses this information to help determine what varieties he’s going to grow in the upcoming season. The OFA Short Course is also a good source of plant material.

“I don’t go to the California trials,” Hammerle said. “Because they’re too damn early in the year and I don’t have the staff to cover operations.” He visits the Cornell University Trial Gardens and is considering a visit to Penn State University’s Landisville, Pa., trial gardens.

He’s had success with several plants including Plush petunias, Accent and Super Elfin impatiens, Oglevee geraniums and Kong Mosaic coleus. Plush petunia sales have increased each year and now he’s getting requests for them. He likes that they bloom fast but don’t get out of control in the container. The color comes on quick and he ships them out fast, which is a huge benefit from the production side of things. One plant that has proven to be a nice surprise is the Taishan African marigold, a first year plant which has replaced other African marigolds. Sales have been very good for it.

Hammerle uses tried-and-true plants because his customer base of independent garden centers and rewholesalers need something they can depend on and know will work in-ground for their consumers. “It’s all about in-ground performance,” he said. “If it doesn’t work for the end consumer, it won’t sell for me.” He cited New Guinea impatiens as an example. “We grew about 40,000 of them and I have only 70 pots left. And I know those will sell,” he said.

For more: Juniper Hill, (631) 589-5677; www.growing4you.com

Surprise sellers
The OFA Short Course, ANLA Management Clinic and the IGC Show have proven to be invaluable resources for finding new plants for Michael Davison of Platt Hill Nursery in Bloomingdale, Ill. Though he does not attend out-of-state trials, he will visit the Ball Horticultural and Bailey Nurseries facilities when they host grower days. His best resource has been the various industry publications.

“The images and write-ups from the various trials are very good,” Davison said.

Diamond Frost euphorbia is one of his favorites. He said it blooms great, has garden toughness and hardiness, and is heat and cold tolerant.

One surprising hit has been Pretty Much Picasso petunias. Customer demand has kept these plants in the greenhouse and garden center. Bloomerang lilac has also received a fair number of customer requests, but Davison has been unable to obtain the plant.

“It’s frustrating to have the demand and not the supply,” he said.

This year, April temperatures were warm and business was up. Unfortunately, Davison said he was unable to offer what consumers were asking for because the growers that supply Platt Hill weren’t prepared for the early warm weather.

For more: Platt Hill Nursery, (630) 529-9394; www.platthillnursery.com