Category Archives: Shade houses

AB Ludvig Svennson’s Climate Screens Give Greenhouse Growers More Control

12 proBy working with one of the world’s leading manufacturers of textile climate and environmental solutions, Agra Tech , Inc. of Pittsburg, CA is able to provide its clients with the ability to control their greenhouse growing applications, regardless of where they’re located or what they’re growing. A fourth generation family business run by siblings Anne and Anders Ludvigson, AB Ludvig Svennson (LS) provides a wide range of Climate Screens that are used to control the climates in greenhouses all over the world.

With headquarters in Kinna, Sweden and with daughter companies located in China, Holland, South Korea and the United States, LS makes energy fabrics that achieve the entire gamut of climate control, including reflecting the sun, blacking it out and diffusing its light evenly, just to name a few. By refining and further developing its Climate Screens over the years, LS has been able to provide more efficient shading properties, greater energy savings and thereby creating a more favorable growing climate for greenhouse growers.

Mauricio Manotas is the President of LS in the U.S. He has been spearheading his company’s operations in North America since the company came to this country in 1996. Manotas has been able to see the Climate Screens industry change rapidly as the technology has progressed. “It’s exciting to be working with some of the country’s leading greenhouse growers at LS,” Mantas said. “On the East Coast, there is more vegetable production and in the West, we’re selling more Climate Screens to companies that are doing research and development and growing flowers, for example. Our products allow our customers to control every aspect of the climate in their greenhouse and that’s why they can guarantee quality crops year round.”

LS features five different Climate Screens. Each has its own distinct purpose, depending on what you’re growing and where you’re located. To suit different growing conditions, the company’s Climate Screens come in more than 100 different variants. They are divided into five families according to their main features, which makes the selection process easier and more accurate.

The main five types of Climate Screens made by LS are

Harmony: Scatters sunlight evenly

Luxous: Provides maximum daylight

Obscura: Total blackout

Solara: Highly reflective/open for ventilation

Tempa: Uses aluminum strips to maximize energy savings

Manotas has been working with Agra Tech, Inc. since day one and appreciates the relationship. “We’ve developed a great relationship with John and Eloise Pound at Agra Tech and I know they were working with LS long before I came onboard. We’re a family business too, so ATI has a special place in our hearts. We’ve worked with them on a lot of projects over the years and we really respect their knowledge and experience. They’re a valuable distributor of our products and we’re proud to be working with them.”

LS just doesn’t sell its Climate Screens—they also bring a ton of their expertise to the table as well, according to Manota. LS and Manota are adept at working with greenhouse growers of all sizes—from 100-200 square feet all the way to enormous 40-acre greenhouses.

“Everything is custom made, so we work project-to-project. Each scenario is completely different, so you can’t ever take a ‘one size fits’ all approach,” he explained. “We analyze every scenario carefully and then we advise our customers about what they require. In many cases, the grower doesn’t know what they need, so we weigh all of the factors—the geography, the kinds of crops to grow and the type of greenhouse they’re using. We study their operation and look at it objectively. That way we come up with a blueprint in the form of a 6-7 page document that makes recommendations and offers them what we feel in an ideal solution. There is competition in this business, so we use our knowledge and experience to differentiate us from the rest. We want all of our ‘climate partners’ to maximize their yield and get the best crops they can, so that’s what we do in each situation. By setting our customers up for success, we hope that they will work for us on an ongoing basis, as they grow and experience continuing success.”

Agra Tech’s Energy Curtains Provide Control and Significant Energy Savings

Agra Tech’s Energy Curtains Provide Control and Significant Energy Savings

By controlling the growing environment in a commercial greenhouse and being able to manipulate the weather at any time, Energy Shield Curtain Systems manufactured by Agra Tech, one of the world’s leading manufacturers of commercial greenhouses, are used by growers throughout the country for a plethora of different uses.

John Pound, owner of Agra Tech, Inc. has seen literally thousands of applications for his greenhouses in conjunction with his Energy Curtains, so he knows the best ways to use them and how to achieve optimum results in almost any greenhouse scenario, he said.

It’s all about control and saving energy in the process,” Pound explained. “By using this product, you can produce better quality plants and that’s what every grower is striving for. By incorporating the fabrics that suit them the best, growers can keep the heat in or get the cold out, depending on their plants, their geographical location and the time of the year.

In short, Agra Tech’s Energy Curtains are retractable interior ceiling curtains system manufactured for use in Agra Tech greenhouses. All Agra Tech structures are factory punched to accept the Energy Shield, which allows growers to add them conveniently after they install their greenhouses and are up and running.

By choosing from a wide range of shade fabrics that have been designed to reflect excess sun back out the roof in greenhouses, Energy Curtains by Agra Tech, Inc. can provide a cooler climate in the greenhouse if desired. By using thermal curtain fabrics, growers can retain more heat in their greenhouse on cool days and overnight. Most fabrics on Agra Tech’s energy curtains have both shade and thermal value, making them versatile and thereby easier to use.

The basic features built into Agra Tech’s curtain systems improve growing environments while maximizing energy savings; enhancing space utilization, and assuring continued problem-free performance. They’re available in Slope-Flat-Slope systems or can be used in a Flat system. All Agra Tech Energy Curtains can be either computer or manually controlled, powered by Agra Tech’s certified motor/gearboxes and controllers. The Energy Shield Curtain System can also be retro-fitted into non-ATI greenhouses.

Agra Tech has designed all of its Energy Curtains for easy installation and drama-free maintenance, Pound explained. “All of our greenhouses are set up so that an Energy Curtain can be added at any point, because all off the frames already contain all of the necessary mounting holes, etc. Many customers will purchase a commercial greenhouse from us and then down the road they will opt to incorporate the Energy Curtain. It’s like when people buy a house and then add a deck or a patio, for example. They’re enhancing the greenhouse’s performance and saving money almost immediately.”

Once installed, Agra Tech’s Energy Shield Curtain Systems work automatically and require little attention, according to Pound. “It’s simple to set up the timing and once you’ve got it dialed in, you can forget about it and concentrate on more important things. In the end, the quality of the plants will improve and that’s our #1 priority. And by consuming less energy these curtains are a smart investment, because they optimize the greenhouse’s purpose and eventually pay for themselves several times over, in many instances.”

Sunridge Nurseries in Bakersfield, California uses Agra Tech, Inc.’s Energy Curtains in all of its 28 ATI greenhouses, as they help the company to produce more than 6 million grape vines annually for wineries worldwide. Eloy Rodriguez oversees the growing of these vines and could not do his job as effectively without his Energy Curtains, he explained.

Our season runs from December through June,” Rodriguez said. “So, we have to keep the vines warm in the winter and cool them down as we enter summer. Agra Tech’s Energy Curtains allow us to completely control and monitor our plants, so that we can produce the best quality season after season. Every morning, we determine how much light we want in the greenhouses, and the curtains make it so easy to achieve. 20 years ago, we had to get up on top of the greenhouses and lay netting along the roof. It was all manual and very time consuming. Now, it’s just a matter of pushing a button.”

Sunridge Nurseries has been slowly replacing its original Agra Tech Energy Curtains, which it began purchasing in 1984, Rodriguez said. “We started changing them for newer ones about six years ago. These curtains will last 10-12 years, so we’ve been retiring roughly eight each year. They’re highly reliable, very easy to maintain and have performed extremely well since the first day we installed them.”

Agra Tech’s Slope-Flat-Slope design includes:

  • A dryer growing climate is maintained due to the air mass below the curtain that enables excellent air circulation.
  • Morning crop shock is minimized because there is less cold ceiling air above the curtain to drop on the crop when the curtain opens.
  • Better energy savings are acheived because of the small air space between the curtain and the glazing.
  • Space is better utilized because equipment can be hung below the curtain, leaving ample room above the curtain for ridge vents.

Agra Tech’s Push-Pull design includes:

  • Push-pull describes the drive mechanics of the system. It is a high strength, low friction, rigid system requiring little maintenance.
  • The curtain is pushed and pulled to open and close.
  • Continuous 1 3/8″ pipes run from end to end of the greenhouse connecting the entire system together. They are driven by steel racks and pinions and supported within low friction roller guides.

All Agra Tech Energy Curtains include:

  • Galvanized steel racks and pinions for long life and low maintenance.
  • Spring steel fabric clips
  • Most support and restraint monofilament cables in industry
  • Full leading edge and gutter seals included

By: Ed Attanasio

Shade Houses provide seasonal low-cost protected space

Shade structures provide protection against wind and solar radiation.  They are a useful tool for modifying the environment and extending the growing season, both in cold and warm weather.

Shade houses can provide frost protection for perennials and herbs during winter.  Temperatures inside can be as much as 20°F higher than outdoors.  Shade houses can also be used to harden off bedding plants before they are shipped to retailers.  Protection of outdoor-grown foliage plants that require lower light levels is also possible with shade structures in some climates.

In nursery operations, shade houses can provide temperature and weather protection year-round.  They can also reduce irrigation needs during summer.  In some areas, the reductions of animal damage helps to pay for the structures.

In garden centers, shade structures are frequently used to provide protection.  Besides providing a covered sales area during inclement weather, they protect the plants from wind, rain and sun.

Protecting plants

Incoming solar energy is converted to heat energy when it strikes plant leaves.  This can result in excessive air, leaf and soil temperatures.  Placing plants under 30-50 percent shade in midsummer can lower the leaf temperature by 10°F or more.  This reduction in temperature, along with a lowering of wind speeds, can significantly lower transpiration water loss during the growing season.

Not all plants require full sunlight to grow.  Most plants can only use a limited amount of light (called the light saturation level).  African violets lose chlorophyll at a light intensity of 1,500 footcandles.  Foliage plants may be burned at a light level over 2,000 footcandles.  Chrysanthemums and geraniums can tolerate about 4,000 footcandles.  Rose and carnation plants can grow under full summer light intensity of up to 10,000 footcandles.

The application of shading is really an art as the level that reaches the top of the plants is reduced significantly by the time it reaches the bottom leaves.

Lath houses

The original shade houses were called lath houses.  They were frame structures covered with wood lath most were made with poles set into the ground with 2-inch framing lumber nailed to the poles to support the lath.  Fifty-percent shade was created by leaving a space equal to the width of a lath between adjacent laths.

When polypropylene was introduced to the greenhouse industry shade houses took on a new appearance.  Wire or cable was adequate to support this lightweight material.  Today, most shade structures are covered with either polypropylene, polyethylene, polyester or a composite fabric that usually contains aluminized polyester strips.

Most greenhouse manufacturers offer some type of shade house.  These structures can be either a fixed-roof or retractable-roof design.  Fixed-roof designs are either rigid frame or cable frame.

Cable-frame shade houses

The cable-frame shade house probably evolved from the shade tobacco industry.  Several thousand acres are covered annually inConnecticutand other states to modify the environment to produce tender tobacco leaves for the wrapper of the best quality cigars.

Posts surrounded by concrete are set into the ground on approximate 20-by-20 foot spacing.  Height can be 8-16 feet.  Deadmen (buried supports) located around the perimeter provide bracing for the tension in the wire.  Stainless steel cable with adjustable turnbuckles are strung between the posts to support shade material.

In tobacco shade houses, the edge of the material is sewn around the wires with a strong thread.  In nursery shade houses, clips or hooks are used to fasten the material.  Shade material hung on the side walls around the perimeter is attached to the upper wire and usually buried in the soil.  It provides wind protection to the plants.

Due to the variables in construction, cable shade houses usually do not carry a design wind or snow load.

Rigid-frame shade houses

In rigid-frame shade houses, the cable is replaced by pipe or roll-formed truss members.  The trusses support the shade cloth.  Instead of deadmen, diagonal Kneebraces, both horizontal and vertical, create the rigid frame.  Post spacing is less than the width of the cable system, usually 10-18 feet.  Shade material can be attached with tek screws or clips.

Retractable-roof shade houses

Retractable-roof shade houses are available from several manufacturers.  They can have either cable or truss supports and usually carry a design wind load.

As solar radiation varies considerably over the day and from season to season, the main advantage of the retractable-roof design is the ability to regulate the amount of sunlight that reaches the plants.  Plant growth increases because ventilation can be controlled to lower temperature.  Ventilation can also reduce disease incidence.  Reducing the intensity of the sunlight can lower irrigation requirements, as both the plants and the soil are cooler.

Both cable and truss-style retractable-roof designs use standard energy blanket technology for opening and closing the shade material.  One gear motor can handle up to 50,000 square feet of growing area.  The shade material is usually stored at the post line.  For areas that receive considerable snowfall, the shade material is stored under a protective hood so that it doesn’t get covered with snow.

Most retractable shade houses are available with roll-up sidewalls.  These use a conventional roll-up mechanism and small gear motors.  This provides ventilation on demand and also accessibility for plant handling.

In areas where protection of the plants from snowfall is important, an A-roof design is available.  The A-roof can be covered with an impervious material that sheds the snow and rain to a gutter for removal.  Supplemental heat can also be added.

For a grower using a conventional 14-foot-wide over wintering hoop house covered with white polyethylene for protection of perennials, herbs and nursery stock, a retractable-roof structure can provide better temperature control.  It can also reduce plant handling costs as the larger area under one roof and the vertical sides allow mechanized handling equipment.

Improved technology and design of shade houses can provide growers with a low-cost option.  They are a useful growing tool instead of more greenhouse space.

The GMPRO on Technology

John W. Bartok Jr. John Bartok is extension professor-emeritus in the Natural Resouces management and Engineering Department of University of Connecticut, Storrs, CT 06269