Spell energy on the ground (aka. repurposed watering can)
At the end of the community day, exactly at 2pm I tried to grab one last spell energy (blue lightning icon) from the map. I pressed the icon and got a pop up that my "Seed and Water vault" was full. I canceled out of the message and tried again, with the same pop up.
I canceled again and went into my Seeds and Water vault and deleted some seed packs. I went back to the map (around 2:01 PM) and selected the "Spell energy" icon and the game gave me some Water.