IMO it seems like over-watering.
Also, 84 F is pretty warm. At this temp you should have a higher humidity, around 65 to 75% -
https://i.imgur.com/L7jOoRH.gif
And the difference vs. the night is huge at 21 F. Such a big difference isn't healthy.
I guess you are keeping the plants warm by leaving the light on 24Hrs?
Although there are a lot of conflicts to ideal lighting schedules, I personally think the plants should be given some rest.
"It has been suggested that, when subjected to a regimen of constant light without a dark period, cannabis begins to show signs of decreased photosynthetic response, lack of vigor, and an overall decrease in vascular development."
https://en.
wikipedia.org/wiki/Cannabis_cultivation
Consider instead to allow a dark period and get a heater to keep the plants warm during that time: http://www.ebay.co.uk/bhp/tubular-heater-thermostat
But then I'm also not an experienced grower, just been reading a lot. So take what I say with a grain of salt if you wish 😁
+1 strain
+3 strains
