Does Anyone Use VPD
- Thread starter Koolbudz
- Start date
There has been a fair amount of discussion in regards to that topic on the forum in the past year or so. I'm using my cell phone instead of the laptop, so it's a bit of a pain in the ass for me to read through a bunch of threads in order to post what I'd consider the most useful ones - but I'll hit a web-search engine, do a simple/quick 'site search of the forum for threads about it, and post a few for you. I'm assuming that at least some of the members who are discussing VPD will actually be trying to make use of the information - but I cannot promise that, lol. But, hopefully, you'll find something of use. Here you go:
Apologies in advance if none of the threads are useful, if I've somehow managed to pooch the links, et cetera. This is the first time I have ever tried doing a site search, open a bunch of links in separate browser tabs, then copy and paste them... on my cell phone. And, since it ended up taking me something like eight minutes to accomplish something that should have taken less than one, lol, I'm guessing it might be the last time. I sure hope it cools off enough tonight that I can run my laptop for more than fine minutes before it overheats and does an abrupt power down
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Vapor Pressure Deficit & What It Means To You!
VPD - Overview Until the last couple years, Vapor Pressure Deficit, was measured mostly by research universities and agricultural laboratories. The tech available to growers these days has enabled us to dial a grow room in very accurately with regards to heat and RH. We all know that cannabis...
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Noob with tons of questions
Hey all this is my first time growing marijuana , i have read aloooot, watched alooot ..but still have unanswered questions a quick brief : ill be growing indoors , soil ,CFL . 1- my first priority is to grow some more seeds, so i bought 10 Dutch passion power plant in regular form , soaked 4...
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Is my RH ok?
this is my set up and stats of temp, RH , ph and ppm my seeds have been planted for Just a day now. I have been talking to people regarding RH and they all say it will sprout at 35% RH with slow growth so does anyone know how I could increase the RH in the tent. Thanks for any help.
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Temperature & Humidity
Hey I just wanted to see what range most people try and stick to for their plants. I've seen some people say keep the humidity around 50-60% and others say higher. I have mine set up at 77.5°F and 62% humidity. I have alot of trouble retaining humidity, I mist it fairly often to try and keep it up.
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Problem with humidity control in tent
I have a 2x4x5 tent with a few White Widow girls and they are in the first weeks of flowering. I have a AC Infinity Cloudline T6 in the tent with a Vivosun filter. I also have a portable A/C unit outside the tent that feeds cold air into the tent through a flexible hose. My problem is that I...
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Thoughts on VPD and more - AT33
High everyone, I'm new here btw. I'm working on my 2nd cycle in perpetual. Today I had a thought. Maybe some genius here can help. The presence of light must create osmotic resistance I think the value would be -/+ based on a set benchmark of humidity. We're getting into osmotic absorption...
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First time grower getting kinda worried over yellowing spots on fan leaves
Hi! As mentioned in the title im a first time grower, and im currently at 2 ½ weeks since the germinated seed started appearing out of the pot. Everything has been going very well untill my humidifier was going nuts and humidifying way to much and a few days later i gave her some veg nutrient...
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Curing process stops under 50% - Is there any science behind this?
I keep reading this and it seems like it's just some kind of myth. Is this written by someone somewhere that's verified by fact? I mean what is it based off of? The reason I'm suspicious is because I just dried my crop until the stems were snappy, and then jarred them up. My hygrometer was...
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Apologies in advance if none of the threads are useful, if I've somehow managed to pooch the links, et cetera. This is the first time I have ever tried doing a site search, open a bunch of links in separate browser tabs, then copy and paste them... on my cell phone. And, since it ended up taking me something like eight minutes to accomplish something that should have taken less than one, lol, I'm guessing it might be the last time. I sure hope it cools off enough tonight that I can run my laptop for more than fine minutes before it overheats and does an abrupt power down
.
DaddyKush
Well-Known Member
I always adhere to the VPD chart all through veg and about the first month into flowering. After that, I toss it out the window and try to keep humidity around 55% regardless of temperature or what the VPD chart says. For example, right now it's 81 degrees in my flowering room and according to the VPD chart my RH should be at 75%. But every instinct tells me 75% is way too high for a plant that'll be harvested in 3 weeks. So I keep it at about 55%.
Nunyabiz
Well-Known Member
I keep to the VPD all through veg.
About 2 weeks into flower I start lowering my humidity by 5% every week until I get to either harvest or 35% which ever comes first.
I've got between 2 to 3 weeks to harvest right now and I am at 45-50%
Next week 40-45%
About 2 weeks into flower I start lowering my humidity by 5% every week until I get to either harvest or 35% which ever comes first.
I've got between 2 to 3 weeks to harvest right now and I am at 45-50%
Next week 40-45%
Yee haw I reckon. Do people not comprehend that relative humidity is relative? In absolute terms, 75% relative humidity at 81°F would be classed as quite fucking humid, lol. There's cheaper ways to grow mold - although if you shot for that RH at that temperature, and then your night temperature dropped into the 60s and you couldn't remove a shit-ton of moisture from your grow space... maybe not too many more likely to. I'm glad you applied a modicum of common sense there. I wish more people would do that, that is too say, THINK before blindly following advice / charts / FAQs / et cetera that they find posted somewhere on the Internet. Look at stuff like that like you would anything else - if the person is as sure that he is right as a religious zealot, lol, then take it with a grain of salt.
I read a thread earlier (when hunting up some links to threads that mentioned VPD) in which someone referenced a YouTube video; the person in the video had, apparently, stated that the correct lights-on temperature for getting cannabis was 71°F. Where do people get this kind of shit? At that temperature, the average cannabis plant isn't even able to use 100% of the light-energy that a hapless newbie might manage to provide with a cheap POS Chinese blurple, let alone the kind of light levels that can be found in a decently illuminated grow space. FFS.
People need to bear in mind the fact that about all that's required to publish something on the Internet (and this definitely - and obviously - holds true for GoobTube videos) is an IQ of at least 62 and the inclination to do so. With the bar set so low... Skepticism is healthy. . . .
No Pain
Well-Known Member
Okay First not all vpd charts are created equal ...second most of the charts that I have seen have a colored scale to follow for the stage of growth . There is an excellent one and its the one that I use throughout my entire grow it also factors in leaf surface temp ...if you are serious about vpd you will get a laser thermometer and monitor your leaf surface temp , anything below 80 degress results in slower growth , Note that just because your room is 90 doesn't mean that your leafs are close to it type of lights and distance play a big factor in this.
now depending on what your leaf surface temp is you are actually in the money zone with your 81 degrees with an rh of 55 In late flower .
you can find the one that is use if you google "Everest Hernandez vpd chart "
| Low Transpiration (Propagation / Early Vegetative Growth) | 0.4—0.8 |
| Healthy Transpiration (Late veg / Early Flower) | 0.8—1.2 |
| High Transpiration (Mid / Late Flower) | 1.2—1.6 |
| Danger Zone (Over / Under Transpiration) | <0.4 >1.6 |
- Thread starter
- #7
Right now my leaf VPD is right around 1.1, with leaf temp average of 72, room temp 75, humidity 53%.... Each plant is under its own Vipar 600 under 12/12 lighting schedule.....#1 is G13/Blueberry Headband and #2 is Godberry.... (Those are 4ft x 4 ft scrog nets)
No Pain
Well-Known Member
your vpd for early flower is excellent ….I would work on getting those leaf temps up ..now that's the trick .Right now my leaf VPD is right around 1.1, with leaf temp average of 72, room temp 75, humidity 53%.... Each plant is under its own Vipar 600 under 12/12 lighting schedule.....#1 is G13/Blueberry Headband and #2 is Godberry.... (Those are 4ft x 4 ft scrog nets)
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