

Help me save my little balcony for the next weeks.
Hi there! Just found this sub!
here is my little balcony. As you can see from the dead and stressed plant, I'm really really bad at keeping plants.
I only recently found a decent balance of watering (Hydrangea on the foreground is recoverying after being in my care, one Ginko dead few weeks ago, the other seems doing fine, potato seems ok), but... I'll soon leave tokyo for several weeks leaving the plants to my wife care (If I'm bad a gardening, she totally ignores it. "it's your plant, you have to take care of them" kind of treatment).
So, I bought a Sonoff water valve that I can automatize. My long term plan is to put a humidity sensor that tells it when to water it. But for now, I have a trouble: the hydrangea really like water everyday, everyone else just every few days. and the heat is coming. (balcony is facing east, so it get really hot in the morning).
Any suggestion?