I’ve purchased the parts I need to build a soil moisture sensor module that uses an XBee instead of WiFi. My gardens aren’t all within range of my router. See this thread for more details and this link for where I got my inspiration. My plan is to assemble the parts and take a crack at incorporating it into the unified firmware code this winter. Just as you suggest, I’d have the XBee wake up at some configurable? interval, take a reading, transmit to the base station, and go back to sleep.