Chasing VPD

[BennoTG]

Morning All
I have a problem, my grow tent prob is reading around 68% humidity about 1.10 VPD obviously fluctuates down to 60% humidity up to 70% humidity temp around 23 Celsius lights off 26/27 light on, running AC infinity grow tent, 2 weeks into flower, if I decrease humidity to 50% VPD goes up above the recommended 1.5 kpa, any ideas on how to stabilise, I'm running dehumidifier and aircon in room however outside humidity can reach in the 90% range at this time of year. Some charts have 65% humidity 1.10kpa at 26/27 degrees Celsius ok for flower and others don't, anyone have similar issues they fixed somehow. Plants are super healthy BTW
Cheers

 

[TCH]

I'd use the VPD as a guide. If the plants are healthy, I'd keep on doing what you're doing. Sounds like you are in the ballpark. If you can keep it at 60% or below and have plenty of air flow/exchange, I personally wouldn't sweat it too much. If you are growing something super dense that is prone to mold, try to drop the rh a bit more.

 

[BennoTG]

I'd use the VPD as a guide. If the plants are healthy, I'd keep on doing what you're doing. Sounds like you are in the ballpark. If you can keep it at 60% or below and have plenty of air flow/exchange, I personally wouldn't sweat it too much. If you are growing something super dense that is prone to mold, try to drop the rh a bit more.

 

[pegboy]

Don't get too bogged down on the numbers. Keep them happy and healthy and you'll harvest some serious bud. I think the interweb makes growing appear much more difficult than it actually is.

 

[BennoTG]

I'd use the VPD as a guide. If the plants are healthy, I'd keep on doing what you're doing. Sounds like you are in the ballpark. If you can keep it at 60% or below and have plenty of air flow/exchange, I personally wouldn't sweat it too much. If you are growing something super dense that is prone to mold, try to drop the rh a bit more.

Thanks for the advice growing green crack and Maui wowie, green crack plant is just cranking, and the Maui wowie strain looks genetically perfect, trying to follow all the rules but there's a few horror stories of people losing their buds to powery mildrew right at the end, I've brought another fan make sure there's plenty of air flow and might do a defoiliate around week 3, thanks again.

 

[BennoTG]

Don't get too bogged down on the numbers. Keep them happy and healthy and you'll harvest some serious bud. I think the interweb makes growing appear much more difficult than it actually is.

Thanks mate definitely heaps of different approaches for sure

 

[Rocket Soul]

I'd use the VPD as a guide. If the plants are healthy, I'd keep on doing what you're doing. Sounds like you are in the ballpark. If you can keep it at 60% or below and have plenty of air flow/exchange, I personally wouldn't sweat it too much. If you are growing something super dense that is prone to mold, try to drop the rh a bit more.

I agree. Chasing signs of great plant health vrs chasing nrs: if you can see the plant looking saggy its not transpiring; use vpd in order to look for which direction to take your environment; tweak it until you get a nice plant stance: that's the correct vpd for the plant, not some nrs in a chart.
25-28C is good temps for flowering under high intensity light,uch lower and the plants metabolism cant keep up. You can flower in 65rh but you need you cannopy to not be too dense and aome air movement

 

[Gemtree]

Haven’t followed vpd in 20 years

 

[amneziaHaze]

you are chasing room temp vpd and not the leaf temperature.they can be a huge difference in the two.all charts are for leaf temperature.meaning allsoo top leafs where lamp is need different vpd then bottom leafs that are in the shades

 

[Rocket Soul]

Vpdchart.com is your friend, you can adjust leaf temp and ambient temp individually

 

[BennoTG]

Went and had a look, makes it easy, thanks easy to understand what's going on now.