The New Computer Program Virtual Grower Will Help in Greenhouse Management Jonathan Frantz, USDA-ARS, Toledo, OH 43606 419-531-1531, jonathan.frantz@utoledo.edu James Locke, USDA-ARS, Toledo OH 43606 Charles Krause, USDA-ARS, Wooster, OH 44691   Greenhouses are complex systems. One management decision invariably influences another in often unexpected or unforeseen ways. As seasons change, management practices may shift from optimizing production for plant quality or “yield” to efficiency and reduced energy costs. These decisions impact the performance of plants, likelihood of disease outbreaks, and labor. Trial and error and “rules of thumb” are not a consistently profitable manner to make management decisions. Often, intuition betrays what is truly best for our specific management scheme. 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? In the following article, I will introduce our efforts in helping you make decisions by using a new computer-management tool called Virtual Grower. Even though the program is not in its final form, we feel that the program is useful now, and therefore needs to get into your hands. Additionally, the program is available, free of charge, at the website http://www.ars.usda.gov/Research/docs.htm?docid=11449. You can also visit this website for future updates and releases. Goals There are many computer-based programs that will help a grower determine management of individual aspects of the greenhouse system, but none that we know of that will do all simultaneously and include potential interactions among the system parts. We have attempted to bring together these computer programming parts into a single program. The goals of this effort are to allow users to simulate different management techniques in seconds and take out some of the guesswork of greenhouse management decisions. When completed, the program should help growers in the US estimate fuel costs for a growing season, see how changing fertilizer and watering affects the operation, schedule growth regulators, pesticides, and algaecides, manage labor, optimize for plant productivity, and help to determine pricing. Greenhouse Energy We have focused primarily on energy requirements for greenhouses. On the main page of the program (Figure 1), you can choose your state and closest city. This loads an historical database of weather for the selected area and allows the program to calculate energy needs based on “typical” weather conditions for each hour during the year. It doesn’t take long when visiting growers to notice how different the structures are among growers or even among ranges. The program allows you to “build” a greenhouse or series of greenhouses that matches your facility (Figure 2). The more time spent creating a realistic version of your greenhouse operation within the program, the more realistic and accurate the program will be in calculating costs. Once a greenhouse is built, the program allows you to input your fuel type and expense (Figure 3). Are fuel prices changing? How much will that affect your bottom line? How much will dropping your greenhouse temperature by a degree or two influence your gas bill? You can play with these scenarios and even take greenhouse sections out of production to see how the costs change. Future Direction of the Program The computer program is a work in progress. We will ask for your input to improve the program so that it is easier for you to use. We are probably missing key ingredients, many of which we may have ignored in our planning. Please tell us your comments, because we truly believe that the program can only help the industry if you give us suggestions on ways to improve it. The program is drab right now and we want to add more graphics to assist in letting a user be more comfortable with the program’s use. Some ideas include seeing a diagram or drawing of the greenhouse you designed, clickable graphics that let you change greenhouse features (i.e. matching walls, greenhouse orientation), and “virtual plants” that grow differently with different environmental and management settings. In spite of these “limitations,” we feel that the program can be useful now as we head into another season of production.