VPD and C02 in flower

[renobambino]

Hey people I was wondering if anyone could help me with this. So I know people generally aim for 1.2 to 1.6 VPD in mid to late flower. What about if you're running C02 and striving for 86F? with a humidity of 65% and a leaf temp of 82F the VPD is 1.5 which isn't to bad. I was wondering would it even matter about VPD in flowering as long as you've got your watering dialed in? I really want the stomata optimally open to take advantage of the c02, can someone explain?

 

[Zill]

Q - Why do guard cells swell and close the stomata? A - To regulate water transpiration, manage high temperatures and regulate CO2 concentration in the leaves. It’s a balance between gas exchange and water loss.

You’re running hot - 85F. My only concern at that temperature, if the plant cannot compensate higher rates of water transpiration, soil too dry, the stoma will shut.

 

[mrsdabfire]

Hey people I was wondering if anyone could help me with this. So I know people generally aim for 1.2 to 1.6 VPD in mid to late flower. What about if you're running C02 and striving for 86F? with a humidity of 65% and a leaf temp of 82F the VPD is 1.5 which isn't to bad. I was wondering would it even matter about VPD in flowering as long as you've got your watering dialed in? I really want the stomata optimally open to take advantage of the c02, can someone explain?

VPD is crucial to consider when you're using supplemental CO2, especially in the flowering stage. With CO2 enrichment, running at a higher temperature, like the 86°F you mentioned, is beneficial because it can increase the rate of photosynthesis. However, it’s important to balance this with the right humidity levels to create an optimal VPD.

At a leaf temperature of 82°F and an ambient humidity of 65%, you're right; you're in the ballpark of 1.5 kPa for VPD, which is pretty good. Maintaining a VPD around this range should indeed keep the stomata optimally open, allowing them to transpire and take in CO2 effectively.