I left home a few days after the previous post. Only a single relay was connected to the irrigation system.
Tânia re-wiring the irrigation relay
Five months later, I'm back home. Tânia from #coolab is with me and together we finally managed to finish this project, although it'll only really be useful in another 3 months from now.
Esp32 4 channel relay and connections
Irrigation system with cut bottle-tops protecting the connections