65F or so up to 75F give or take a little bit
The plant starts to die at around 90F.
The colder the nutrient solution, the less up take by the roots
same thing when it gets to warm, theres less up take by the roots.
(the plant slows down). I think you could go down as low as 50F
I think thats about the point where you start to kill it.
Cutting should be 75F to 85F. Same thing around 90F you start to
kill the cutting, but a higher water temp say 85F makes your cutting root faster.