If you water your plants by hand, swapping a battery isn't too big a deal. Solar might work if your plant is consistently in direct sunlight, but you need to ke

If you water your plants by hand, swapping a battery isn't too big a deal. Solar might work if your plant is consistently in direct sunlight, but you need to keep some amount of charge to keep at least the RTC running so that's a hurdle you'll have to ponder. I don't have any estimates of battery runtime or anything, but I'll note that WiFi is battery-expensive and takes a few seconds to actually connect to the desired network so you'll want to wake WiFi as little as possible. Meanwhile, actually doing sensor readings can be done pretty often. So it's entirely feasible that you might do a bunch of sensor readings and then upload them all in one go to save power. From there on out it's a question of how much power a sensor draws, how much power the device draws, and how often you want to wake it.