Humidity / Temperature Chart : Helpabrotherout....

[Will Rogers]

Okay, I got this link on this forum, I think.
It looks super useful.

Please let me know if I understand it correctly:

http://opennlabs.com/vpd/VPD_calculator.php

1. So if I'm starting seeds / seedlings and my room is 85 degrees, the humidity should be perfect at 74%.
?

2. If I'm in the flowering stage at 85 degrees, the humidity would be optimal at 55%.
?

Is this correct??

What does VPD stand for?

How to best increase / decrease humidity in small space?
(Where I live I imagine the humidity will always be high.)

Thank you for your time.

 

[Mañ'O'Green]

VPD = vapor pressure deficit Read about it here:

http://www.just4growers.com/stream/temperature-humidity-and-c02/vapor-pressure-deficit-the-hidden-force-on-your-plants.aspx

 

[Give Pizza Chants]

Is the temperature and humidity part of the chart still useful without the VPD factored in?

I read and watched every bit of the VPD link and it's way, way over my head.
I was an art major and this is like math equations.

 

[KIS]

This podcast episode and chart may be helpful. https://www.kisorganics.com/pages/cannabis-cultivation-and-science-podcast-episode-30

 

[Simplicio]

What does VPD stand for?
How to best increase / decrease humidity in small space?
Thank you for your time.

Vapor Pressure Deficit
I own several top fill ultrasonic humidifiers, and a couple top fill forced air humidifiers.
To decrease humidity, increase exhaust fan speed, unless outside humidity is too high.
Rising temps decrease humidity, falling temps increase it.

Here's a simplified version of the VPD chart.
Subtract 5-7 F from air temp to get leaf temp, then use the chart with leaf temp.