Published 16/05/2011

Reasonable Retrofits

Growers who aren't in the position to replace older structures can improve them economically with a number of upgrades.

Today’s economic climate isn’t exactly ideal for taking on large investments, like the debt you might incur constructing new greenhouses. But while some say the best greenhouse is one that is paid for, this isn’t always true, according to greenhouse engineer A.J. Both of Rutgers University. Both says growers should evaluate their structures’ efficiency before deciding whether building new or retrofitting existing greenhouses is the right decision.

“I say a greenhouse that is paid for is a greenhouse that is ready to be replaced,” Both says. “Every situation is different and yes, building new will cost money, but so does operating an inefficient older structure. A thorough economic analysis may be needed to evaluate the best option.” 

Kurt Parbst of shade cloth and screen manufacturer Ludvig Svensson, agrees, but offers some goals for a successful approach to structure improvement.

“Sometimes greenhouses that are paid for are very inefficient in their utilization of land, labor, energy and water,” Parbst says. “Crops should be grown in facilities that maximize return on investment. In some cases, that may require updating old facilities or replacing them. Labor and energy are often the two largest expenses and efforts spent here will have the largest return.”

When New Isn’t Possible
Still, even in the best of times, most small to mid-sized growers cannot afford to replace their structures. The next best thing, then, is to upgrade existing greenhouses with inexpensive technologies that boost production efficiency with less risk involved.

         
Reasonable-Retrofits

“Improvements to enhance the quality of existing greenhouses include reducing energy consumption and labor requirements using mechanization instead of automation, optimizing space utilization, implementing a preventative maintenance program and learning from your fellow growers without doing exactly what they do,” Both says.

He suggests growers investigate energy conservation by increasing insulation, reducing air leakage, installing high-efficiency heating systems, using the cheapest fuel source available, installing variable speed pumps and motors and manipulating crop scheduling to reduce energy consumption. Growers should also aim to improve environmental controls, Both adds, including replacing on-off thermostats with a computerized system operating a more sophisticated control algorithm....

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