The present invention makes it possible to reduce effects of failures in a control device and easily handle changes in layouts of jointly used equipment in a plurality of agricultural greenhouses. A plant growth system is provided with a plurality of agricultural greenhouses (10). A first sensor (11) monitors an environmental element affecting the growth of plants for each of the agricultural greenhouses (10), and a second sensor (21) monitors an environmental element outside of the greenhouses (10) affecting the growth of the plants. An individual device (12) is provided for each agricultural greenhouse (10) so as to adjust the environment for growing plants, and a common device (22) is used jointly by all of the agricultural greenhouses (10). A control device (13) is provided for each agricultural greenhouse (10) so as to control the individual device (12). The second sensor (21) and the common device (22) are connected to a single control device (13), and the remaining control devices (13) share information about the second sensor (21) and the common device (22) by communicating with this control device (13).
