Is my vpd close? and more questions

[Akabudz]

Hi all, I have recently switched to led, my temps at canopy level have dropped by around 4-5 deg

I now have lights on 23-24 deg C, and RH 45 to 50%

Lights off 19 to 21 deg C, and rh60 to 63%

Should I be looking at leaf temps at canopy level instead?
Thanks

 

[TripsRabbit]

 

[TripsRabbit]

Humidity is high in your dark cycle, use a dehumidifier or risk bud rot.

 

[Akabudz]

Thanks trips, mmm with my tents position and size I am unable to use a dehumidifier, any more suggestions?
Air flow is very good, I am in a 2x2ft x 6ft tent.

 

[Aqua Man]

Hey bud there is an app called VPD calculator. Its easy to use.

Don't go by online charts unless you want to risk issues. I would suggest an IR temp gun to check leaf temps. I cant stress how important leaf temos are in the equation

This thread may help. You can make your own VPD calculator if ya skip to the end.

VPD (vapor pressure deficit)

Ok i was gonna sit down and write out a whole article but i have been lazy so instead instead I'm going to copy paste because im lazy. This is not my work so let start. You may find this very long but its worth the read. Some may want to skip ahead. I have added here and there to what i feel is...

www.thcfarmer.com

 

[TripsRabbit]

Grow mold resistant strains?
I have my dehuey in the room my tent is in, I dehumidify the air being pulled into the tent. Late flower is really the only time you need to worry about it.
Your plants will grow much better at the right vpd tho.

 

[Akabudz]

Hey bro, thank you, I will check leaf temps an hour after lights on with IR gun,
Will check out that calculator now thanks again

 

[Aqua Man]

Link for anyone.

VPD Calculator - Vapor Pressur – Apps on Google Play

Simple calculator to generate VPD based on Air/Surface Temps and Humidity.

play.google.com

 

[Akabudz]

Thanks bro, i am growing critical Kush which the vendor states is very good for mould resistance.
However I'm now at a stage where I want to learn how to dial my environment in more so, and learn more about what effects plant uptake of water /nutes etc.

 

[Akabudz]

Fantastic bro thanks
For some. Reason I all ways fail to look at what apps are available lol

 

[Aqua Man]

I just noticed it has the ideal VPD for stages of growth right in the app lol.

 

[Akabudz]

It does indeed bro, tahanks again,
I will post where i am at in 3 hrs or so

 

[Akabudz]

OK over 1 hour from lights on and I get.. See image,
I think my only problem is lights out, will check a few minutes before lights on tomorrow.
How am. I looking?

 

[Akabudz]

I'm thinking with lower temps and higher rh in lights off I will need to do some changes.
Will see tomorrow just before lights in

 

[Akabudz]

That was around the centre of leaf temp for leaf temp corners were 22

 

[Aqua Man]

Plants don't really transpire at night so its best to keep the RH lower than the lights on period as there is no real benefit.

This is where PM can become an issue.

High RH at night with low RH day.

 

[Akabudz]

Thanks bro, I'm a little trashed so could you please 3xplain that in simple terms?

 

[Akabudz]

Lux, Centre and corners of tent

 

[Akabudz]

Centre

 

[Akabudz]

Shit I'm on fire lol, centre highest, lower reading corner lol