Spent the last month wiring up my vertical lettuce setup and it's finally running on its own. Twelve ESP32 boards total, each one doing its own job so nothing is a single point of failure. Four of them just collect temp and humidity readings and push everything to a Google Sheet so I can look at trends. One runs the misting lines on a timer, one watches float switches and tops off the reservoirs, one handles the intake and exhaust fans, and the rest each manage a single grow bin. The bin controllers were the fun part. Every tote has a small pump that drains it when the float switch says the level is getting high, so if one board dies I only lose one bin, not the whole room. That was the whole point of spreading it out instead of running everything from one microcontroller. Biggest headache was the MOSFET boards. The ESP32 puts out 3.3v on its pins and some of those boards just wouldn't trigger reliably til I figured out a workaround with the indicator LEDs. Fiddly but it works. Also learned the hard way to keep the electronics box up high and away from any splashing, and to fuse the 12v lines.
Next step is getting the pH and EC dosing automated instead of me mixing by hand every few days.