Vapor pressure deficit (VPD)- are you paying attention to it?

[dethswatch]

I'm looking at starting to keep my temp/humidities within the 'ideal' vpd range.

If you've tried it, have you noticed any difference?

Is there any info on orchids and vpd? Either there isn't much, or google's failing me.

Thanks

[Fernando]

I just try to keep RH as high as possible.

[Ray]

While one could argue the physiological issues associated with maximum humidity, I think that from a practical perspective, it's not worth worrying about.

[bil]

In all honesty, to me that way lies madness. After all, wherever you look, humidity varies from hour to hour.

[dethswatch]

Originally Posted by Ray

... think that from a practical perspective, it's not worth worrying about.

I agree, except that I'm automating it all, so the computer gets to worry about all of that.

Do you have any feel for how much it might influence growth, etc, vs just hitting a temp ~80ish and H range of 70-75%ish or whatever's working for a particular cultivar?

The weed guys apparently are experiencing good results and the academic literature I've read says good things, but I can't find anything relating to orchids...

---------- Post added at 11:57 AM ---------- Previous post was at 11:56 AM ----------

Originally Posted by bil

...After all, wherever you look, humidity varies from hour to hour.

My robot's taking care of that for me. I just tell it what I want...

[jkofferdahl]

I think that sometimes just about anything can be taken too far.

[Fernando]

As many orchids are (potential) CAM plants, they will suffer less from high VPD.

As I live in a place with widely changing HR, I know that some genera (Stanhopea, Catasetum, Galeandra, Chysis, Gongora etc) don't grow well or at all.
As soon as they get into the growbox, they seem happy.
But it does not really make sense to look at one parameter in an isolated way as all them them work together and have synergistic effects. So, low RH and strong air movement is really an issue, as I know from experience.
And very high tº are somehow smoothed with high RH.

BUT - if you chose a high RH keep in mind that this is perfect, too, for fungus. So high RH should be combined with high tº and good air movement.
RH should never be so high, that you get wet leaves at night (dew point)!