After careful consideration, I decided to stop the indoor grow and go outside with the 1 remaining Sweet Cherry Kush.
I hope the switch from canna mineral fertilizer to green house feeding biogrow + enhancer works, as I don't want to mess around with mineral fertilizer outdoors.
It's a real shame that out of 4 plants only 1 really survived, but 2 were severely stunted and 1 slightly stunted with very slow growth. That's why the tent is being cleared for a fresh start (see new grow report).