Built a simple hydroponics growing container with an ESP 8266. Code at https://github.com/cmdr2/farm The seeds have been planted - 18 tomato seeds spread across 6 planters (aka plastic egg carton with a plastic wrap to build the humidity). For the plumbing system, I’ve gone for a simple design. It has two tanks, stacked vertically over each other. A motor switches on at preset intervals, pumps the nutrient solution from the lower tank for a preset duration. A smaller hole (compared to the inlet pipe) in the upper tank (containing the plant roots) drains the water back to the lower tank. For fun, an emergency cut-off could’ve be built at the top of the upper tank (using a water-level sensor). But for now, that’s not in scope.