You can use more than one Spruce Controller with a single SmartThings Hub to add zones to your network.
Each controller just needs to be within range (~150ft if you have walls obstructing, or 300+ft with clear line of sight) of either the SmartThings Hub or the other controller (the controller acts as a Zigbee repeater). You can also use third party Zigbee repeaters to extend the range if necessary.
Currently, scheduling with multiple controllers in a master-slave configuration is only supported with the Scheduler SmartApp (not the web app). If using Spruce Sensors for automatic scheduling, we recommend that you do not share the same moisture sensor between the two controllers.