Yellowing leaf/ leaf rolls ? VPD might have somthing ta do with it. VPD notes. - Page 2 - Cannafornia Seeds - International Cannagraphic Magazine Forums

jammie · 02-26-2013, 11:43 PM

ps- i have my humidifiers on the same timer as my light, otherwise temps will drop, humidity will approach 100% and condensation will occur on the leaves. that will also increase risk of PM.

DamnUglyDogE · 02-27-2013, 12:03 AM

Quote:

Originally Posted by jammie

excellent article AD. i feel the key to avoiding PM is good air circulation. i use an intake, exhaust and small circulation fans in an 8x8x10 grow room and have never had pm in spite of humidity levels like yours (70-80)

Thank you jammie..

Excellent point. Air circulation is a key factor with any set up for many reason and is truly a art form within itself. .
Not too much
not too little
not direct
yet air movement under every leaf and so on..lol

I have great air flow in flower and poor when vegging. As a result I brought PM into flowering and air movement did not seem a factor once established.

Seems air flow is great as a preventive element and mearly helpful once PM has a hold..

I guess one way ta look at it's is...
Get it done right - from the start - or go home...

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OakyJoe · 03-10-2014, 09:54 AM

Very nice and helpful! Maybe you can spread this Thread

Catatafish · 03-14-2014, 05:45 PM

Will vpd problems (low humidity...really low) in veg show up as a MG def?

I have some stuff in veg that no matter what you do shows MG def. Run off/ ph / ec / temps is all good. Just really low RH. I have soil and coco and both will do it.

I have never vegged in this closet before so im suspecting something with the enviro is causing it. My airflow isnt the greatest in there at the moment either but i am trying to adjust while still keeping humidity up. Just added a humidifier and can get it up to about 45% or so with temps going from 70-78 thru out a full day.

Blayz'd · 10-24-2015, 06:49 AM

Good information. Easily understandable. Those tables are helpful. Thanks

Baloni · 11-20-2015, 11:39 PM

What is better with VPD??

A) canopy RH 65-72 canopy temp 28.5-29.5C
bush RH 70-75 bush temp 25.8-26.5C

B) canopy RH 45-55 canopy temp 26.5-27.5C
bush RH 55-60 bush temp 24.8-25.5C

Blayz'd · 11-24-2015, 06:35 AM

Quote:

Originally Posted by Baloni

What is better with VPD??

A) canopy RH 65-72 canopy temp 28.5-29.5C
bush RH 70-75 bush temp 25.8-26.5C

B) canopy RH 45-55 canopy temp 26.5-27.5C
bush RH 55-60 bush temp 24.8-25.5C

I'd prefer B. Especially later in flower. If you watch the plant they will show you what they want. If leaves start curling over like in the OP then the temp is too high and humidity too low.

MJSoft · 11-19-2016, 10:08 PM

I think i've seen this, now i understand it to a much higher degree, thanks DamnUglyDogE G , true education!!! Great post n thread!
Sharing is caring indeed.

02-26-2013, 11:43 PM	#11
jammie ganjatologist Join Date: May 2008 Posts: 1,589	ps- i have my humidifiers on the same timer as my light, otherwise temps will drop, humidity will approach 100% and condensation will occur on the leaves. that will also increase risk of PM.
	Quote 1 members found this post helpful.

03-10-2014, 09:54 AM	#13
OakyJoe OGJoe Join Date: Apr 2013 Location: No sun, where I'm from it's always overcast Posts: 2,469	Very nice and helpful! Maybe you can spread this Thread __________________ Das maximale Volumen subterraner Agrarprodukte ist reziprok proportional zur intellektuellen Kapazität des Produzenten Life is better than you can even imagine. Life is everything. Life is love. I'm free from your spell Oh I'm free, free, free now I'm free from your spell And now that it's all over All I can do is wish you well Plants require 18 essential nutrients to grow and survive, classified by their importance into macronutrients (C, H, O, N, P, K, Ca, Mg, S) and micronutrients (B, Cu, Fe, Mn, Zn, Mo, Cl, Co, Ni). Study Tip! Nutrients may be mobile or immobile in the plant and in the soil, which influences redistribution of nutrients and display of deficiency symptoms, and the fertilization of crops. Nutrient demands change throughout the life of the plant, in general increasing during vegetative growth but decreasing during reproductive development.
	Quote 1 members found this post helpful.

11-19-2016, 10:08 PM	#18
MJSoft Member Join Date: Apr 2011 Location: everywhere Posts: 103	I think i've seen this, now i understand it to a much higher degree, thanks DamnUglyDogE G , true education!!! Great post n thread! Sharing is caring indeed. __________________ CANEPA CA.NE.PA.SA.
	Quote

03-14-2014, 05:45 PM	#14
Catatafish Senior Member Join Date: Dec 2013 Location: Go For It Go For it Posts: 1,325	Will vpd problems (low humidity...really low) in veg show up as a MG def? I have some stuff in veg that no matter what you do shows MG def. Run off/ ph / ec / temps is all good. Just really low RH. I have soil and coco and both will do it. I have never vegged in this closet before so im suspecting something with the enviro is causing it. My airflow isnt the greatest in there at the moment either but i am trying to adjust while still keeping humidity up. Just added a humidifier and can get it up to about 45% or so with temps going from 70-78 thru out a full day.
	Quote

10-24-2015, 06:49 AM	#15
Blayz'd Newbie Join Date: Feb 2009 Location: As within, so without. Posts: 23	Good information. Easily understandable. Those tables are helpful. Thanks
	Quote

11-20-2015, 11:39 PM	#16
Baloni Member Join Date: Jul 2012 Posts: 115	What is better with VPD?? A) canopy RH 65-72 canopy temp 28.5-29.5C bush RH 70-75 bush temp 25.8-26.5C B) canopy RH 45-55 canopy temp 26.5-27.5C bush RH 55-60 bush temp 24.8-25.5C
	Quote