Mr Wizard makes another stab at it

[MrWizard]

Little help here please!

See this post and weigh in if you can!

Growing by the numbers

I thought the whole idea of VPD was to maximize transpiration? Are you saying that VPD alone doesnt max it out? Is it something more like this? Proper VPD maximizes transpiration at a given temp, but the higher the temp the higher the volume of transpiration?