I am a new grower to start off. I have the ACI controller 69 Pro. I have read through this forum and found people to advise not to chase VPD if you don’t have all the necessary equipment. I have the exhaust fan humidifier dehumidifier. Basically I’m wondering if I should focus more on just the temperature and humidity keeping it in the ranges advised. I’ve included a photo of my “daytime”. Currently in flower on the 12/12 cycle. Temperature and humidity seem to be in a good range but VPD is always way off and in the danger zone. Causing me stress but the plants seems to look fine, lol. Just couldn’t really find anything that said one way or another. Is it just personal opinion or is one the right way? Thanks in advance.
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morning Fitz…unless you are in a lab with all the variables dialed in then trying to get VPD perfect will not accomplish much in your grow… what I grow by is during seedling phase I try to keep the VPD close to 1 …maybe just a bit below or above…then after that for veg and flower I do my best to keep above 1 but less than 1.5… think of VPD as allowing the plant to give off moisture…during seedlings you want the plant to keep all the moisture but then in veg and flower you want her to sweat… just my experience… Friday the 13th!
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Yup. Concentrate on your temps and humidity. VPD will get in the ballpark, but dont chase it. Ive spend well over 3 grand trying to get my environment right and gave up and just started watching other variables. Welcome to the forum and Happy Growing 
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Okay awesome thank you. One small follow-up question, I have been using this chart that I found on this forum. I’m in week 2 of flower should I try to stay where everyone says around 50% humidity no matter the temp or if my plans were say around 84° would I want my humidity to be around the 70% mark like the chart shows or is that detrimental to the flower stage?
Side note thank you for explaining VPD the way you did it helps it make a little more sense to me
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Thank you for your response. I can imagine I’ve noticed already this little hobby I decided to partake in has started adding up rather quickly, lol. I will try to learn in advance from your experiences.
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If youre in week 2 in flower, keep your temps between 75 and 80°F and your humidity (RH) between 50 and 60. When the plants are transpiring, youll see spikes in your humidity, but its all good… its normal.
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Okay thank you I was just confused on whether you should follow raising the humidity as the temperature rises or keep it in the strict range of 50 to 60 in. I just grabbed 84° in early flower off the chart for an example. My normal reading during my daytime are around 78° and 51% humidity. I don’t know why it was spiked in my screenshot to over 80 I think I need to find a way to shade my sensor.
I recently moved my plants from a 4x4 into a 8x4 and added a second light so I can split them up more evenly and maybe get better light to them all and have been seeming to have issues ever since on consistency LOL.
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Ive heard a lot of talk about “chasing” numbers and have to agree BUT from my local grow buddy is weeks into veg using the 69 pro set up and he reports that it so easy he just sets the desired VDP and the system does all the Chasing. According to him, his #'s have been spot on all grow so far. The controller turned on or off on all equipment as needed and controls temp,humid,air flow ,lights every thing but feeding and watering.
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Yeah mine was spot on & perfect all the way through veg as well. Then as soon as I started flower I moved from a 4x4 to an 8x4 and everything just kind of went downhill. Now I’m not sure if it was because of flower or because of the tent change or a culmination of both haha.
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You all but doubled your space, did you add more air flow equipment , larger humidifier and ect.???
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Yeah I went from a 4.5 L humidifier to a 15 l. Upgraded to a bigger exhaust fan, turn the old fan into an intake fan. Have the oscillating fan, now have a dehumidifier as well and the heater.
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Ive set my 2x4 tent up for VDP w/69pro myself. Will start as soon as I can.
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If i was in a tent, vpd might be easier to control, but in a 12x8 rocking 2000watts with a 12k ac and 8in exhaust, its hard 
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Good luck when you grow!
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That sounds like herding cats may be a little easier.
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I have 2 mommas with a litter of kittens each… herding cats is way easier
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Maybe it’s less fidgety in a smaller tent. My buddy is in a 3x3. I’m in 2x4. But his experience has been set and forget more or less. All of his equipment turns on or off and run as long as the controller says to! His #'s have been consistent so far.
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This is my approach and most hobby growers. Setting and maintaining VPD is ideal in a controlled environment like the indoor commercial growers have 
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you are welcome and for your other question I believe you got some good responses to this…in flower high heat and high humidity are your enemies…between 50-60RH is a sweet spot and IMHO is the one that if you can only control one this is the one… but must of us go for the best balance we can achieve in our home grows.,…
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Fits I think we are vertually at the same place. I picked up the ACI T3 humidifier in hopes it would help a little with temp as I have zero control there. Then learned a out the VDP. It has me very courious.
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