So, after I've gathered all the components I needed for a basic test I managed to start the pump and do some test in order to check if the Andoid Application and the nodejs server was communicating good, so the app at the moment can only manage how many seconds the pump will stay on and a simple button to make start the water flow. Here the result:

Next steps will be to add a couple of water solenoid valve and programming the server and the app to manage more than one plant.