Virtual Grower is a free computer program designed to assist growers calculate their heating costs at many U.S. sites. Jonathan Frantz at USDA, writing in HortTechnology, said the program uses a weather database of typically hour temperature, light and wind information at 230 sites from the National Renewable Energy Laboratory in its calculations. Growers can provide inputs regarding their structure design and building materials along with their specific type of heating systems and heating schedules. The program predicts heating costs based on typical weather at a selected location. Growers with an Internet connection to local weather forecasts can make shorter term predictions with forecasts of 2 days or less. The program can also serve as a platform to which other features can be added including plant growth and crop scheduling.