I keep min and max as well for each moisture sensor, but I also keep a DRY and WET value for each sensor (wet=in water)Are you relying on only the sensor data for watering? When designing my system I'm trying to think of as many backup plans as possible. I worry about a faulty sensor and was thinking of have a configurable min/max time between watering, each plant would have have a configurable amount of water, that way veg and bloom can have separate reasonable values. If a min or max was used then of course I would like it to e-mail me.
My min and max are of historical readings, so the lowest its been, and the highest, so I see that's not the same as you're talking about.
For my automatic watering, I have a flag which I have to manually set to allow the system to water based on the sensor, AND I also store an Auto Water level. Because min and max can be thrown off by a faulty sensor reading, I decided that I would "approve" auto watering once I determined the value based on recent levels when I hand watered. Make sense?
I was going to add a time limit, so it can't water more than once in a specific time, but I'm not sure I need that. I am taking precautions in case it does overwater... The floor under the pots is plastic lined with a lip, like a small pool
For each "switch" (which is the relay controlling the water pump) I can configure the ON time, so once I've determined how long it takes to pump my normal amount of water, I just plug that number in, and every plant gets exactly what it needs, and can be adjusted...
I'll be honest with you, it's a lot easier to just look at the plants and decide if they need watering