A study in Japan looked at using computers to control the environment in commercial greenhouses. Since 1979, they have been using microcomputers to help manage the conditions inside these greenhouses. In 1990, there were around 48,811 hectares of greenhouses in Japan with some using microcomputers for control. Out of these, 571 glasshouses and 470 plastic houses used microcomputers for environmental control. There are about ten companies making these microcomputers for the greenhouses. It's essential to note that this data does not include the equipment used for soilless plant growth methods.