New Software helps Growers Assess Cost of Greenhouse Structure

Wouldn’t it be great if greenhouse growers’ mistakes never cost them any money? For example, what if you learned before you invested in that expensive new heating system that generating heat was not your real problem, it was retaining heat? Armed with that information, you could invest in some better insulation strategies that are a whole lot cheaper than a new heating system, and actually have more of an impact on your greenhouse environment.

But how do you learn that without making mistakes, i.e. trial and error? Now you can make the mistakes virtually, that is, in a computer simulation. This way you can simply take them back, make a different decision by plugging in new numbers, and see how your new management strategy pays off. Only after you’re satisfied with the results do you actually implement the changes. That makes a lot more sense, doesn’t it?

It does to Jonathan Frantz, a research horticulturist with the USDA-Agricultural Research Service team in Toledo, OH, that has produced a software program called Virtual Grower. “Trial and error and rules of thumb are not consistently profitable methods to make management decisions. Often, intuition betrays what is truly best for your specific management scheme,” says Frantz. “Rules of thumb are developed based on an average grower in an average year with an average greenhouse structure. How often do those conditions apply to you?”

No More Guesswork

The software allows you to “build” a greenhouse before you ever get started on the actual construction. With just a few mouse-clicks, you make the same decisions you would when building a real greenhouse. Glass or double-layered poly? Gutter-connected or Quonset-style houses? Quite simply, you make the same decisions you normally would, but you get to see the results before making big investments. Actually, your only investment is time, because the software is available free at: www.ars.usda.gov/services/software/download.htm?softwareid=108.

How about fuel? There are an astounding 29 fuel types from which to choose for each greenhouse you build. The choices range from the traditional, such as natural gas or propane, to the nontraditional, such as corn cobs or rubber pellets. Frantz thinks the wide range of fuel choices is a huge asset for Virtual Grower, both now and in the future. “This segment of the industry will undergo many changes in fuel type availability, costs and heater efficiencies in the coming years,” he says. “Many of these may cause growers to change from what they are using now to a more nontraditional alternative fuel or heater type.”

Frantz is constantly keeping an eye to the future, as Virtual Grower is continually evolving. A computer programmer, Bryon Hand, is working on it full-time, not only employing more graphics to make it easier to use, but making changes and additions to the program. Many of these changes have been suggested by growers. “With the early versions we went to local growers and they told us what they liked and didn’t like, such as buttons or drop-down menus, for example,” says Frantz. “For the program’s sake, I like it when they say, ‘This really stinks.’ I’d like to get a lot more feedback from growers.”

Full Of Surprises

Since embarking on the project a little over two years ago, Frantz says that he has been struck by a number of things both about the software and in people’s reactions to it. To wit:

• Heater efficiency is critical. It’s measured on a percentage basis, and growers can plug in any value from 0 to 100. “It’s amazing what a huge impact a single percent can have on a greenhouse over the course of a year, so growers should make sure their heaters are in great working order,” he says. “Maybe it makes sense to pay that high school kid eight bucks an hour to go around and clean all your heaters.”

• As they add more and more components to the constantly evolving program, it gets a lot more complicated. The one they are working on now, to see how various factors impact plant growth, is a good example. “I thought it would be a lot more complex (for the team to implement),” says Frantz, “but it’s insanely more complex.”

• He’s received a lot of interest from other countries in the program. That’s a bit of a surprise because the software is based on U.S. weather stations, so it’s of no practical use to foreigners. (The weather data can only be modified by Frantz and his colleagues.) “Maybe they’re using it as a teaching tool,” he speculates.

• But maybe that interest shouldn’t be too much of a surprise, considering the warm initial reception Virtual Grower has received from U.S. growers eager to take their greenhouse plans for a test drive. “It seems,” says Frantz, “to have filled a need.”