serious question about VPD value in the tent

1-1.2 is alright for early flower just keep the hum and airmovement up when it goes higher Your reader should read the transpiration on the leaves wich one of these does it better idk Mine hangs like 50 cm above the canopy to get a wider picture.

The air that is directly around the leaf's stomata is what matters. With good circulation it should not be a large offset from your probes that are placed intercanopy. However, expect a up to a -5F offset due to evaporation. Leaf surface will be coolers than the sorrounding air. Now you can worry about that or just ensure it's a consistent measurement. Whatever offset results isn't entirely necessary to know. if it is consistent you can work with it well enough. It may not translate as well for others, but it'll be something you can reference and compare with confidence. form a baseline using a specific VPD, based on where you rprobes are.. observe and adjust.. compare any results from adjustments back to baseline. mix and repeat. OBviously sample size is relevant, or using clones would be helpful to paint a clearer picture too. I see a fairly wide range for VPD suggestion in flower... and, for each phase in life cycle for that matter. Never know if they calculated it accurately, either. So, trial and error is inevitable. Make sure your baseline is solid across a few strains before experimenting. If you have nothing to compare to, then you have no idea if it helped or not. Even then it can be blurry. Anyway, expect it to be a bit lower temperature than the probe reads. Might take a tenth or two off VPD.