Technical Abstract: Greenhouses are complex systems. One management decision invariably influences another in often unexpected or unforeseen ways. Trial and error and “rules of thumb” are not a consistently profitable manner to make management decisions. A new computer-based management tool called Virtual Grower was released in January, 2006 and was developed 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. In the original version, users could choose the state and closest city, which loads an historical database of weather information for the selected area and allows the program to calculate energy needs based on “typical” weather conditions for each hour during the year. The program allows for “construction” of a greenhouse or series of greenhouses that can match existing facilities. Once a greenhouse is built, the program allows you to input your heating schedule, fuel type and expense. The newest sections of Virtual Grower allows a user to add energy curtains, generate reports, define additional custom schedules, and even get minimum recommendations for heater sizing.