Environmental controllers

[4maggio]

I'm at 22 days bloom at my current grow (Original Family Big Buddha Cheese) but this isn't about that.
This will be y second grow featuring a 400w LED in a 2x4 tent. The first run was just keeping it at 85F/60%rh, period.
This run, currently 22 days into bloom is also featuring for the first time an environmental controller, in my case AC Infinity just because, by happenstance, I had a couple fans by them on hand already. I've become more aware of VPD and the control humidity has on it.
I've been pushing, pulling, adjusting adding and subtracting trying to get the VPD number I want during veg and now bloom.
But how does one know if those temps and rh%s are correct? Although they have been growing nicely.

Today, I concluded, and made a unilateral decision with myself, to use the mercury filled thermometer and mechanical humidity dial as the baseline for temp and RH in the controller. Adjust them both up or down to match the analog/mechanical devise.
Anyone have a better way? If there is one please let me know. My infrared thermometer is ok with analog temperature too.

I've had some great runs with HID and 79F/60%-45%RH.. but this plant, at this point in time, is the best looking girl I've ever run.
Every leaf is 'perfect' I'd put up a pic or two but I suk at photography and the deep green leaves look nothing like the pics I took and that I don't know how to get from my phone to here anyway.

 

[4maggio]

Why can I only see this if I 'search' "controllers"?

 

[Rocket Soul]

Its easy to get lost chasing decimals of vpd. I argue for more following it more loosely and focus on just looking at the plant and what its doing. Youre not after following vpd just cause people online say you should do it; youre after the plants response to correct vpd: transpiration. Are all leaves erect with leaf boners? Your in good range. Is the plant with saggy posture and ppots take time before dry? Look up your vpd values, adjust towards them, and read your plants again

If can see how hard you infinity run your extraction on your controller or just measure the tine between rev up and down while the fan is on setting for controlling rh: the harder it has to work, the shorter the rev down cycles, the more humidity your fan is having to remove; the more the plant is transpiring. VPD is not something your following for its own purpose, you do it so that the plant sucks watter as much as it can, a great correlate to good plant performance. When you feel youre getting it just right: raise light intensity and nutes in middcycle 3-4 week, usually here, when nicely dialed in, the plant can take tremendous almost infinite light as long as your spectrum is not deficient.

 

[4maggio]

Its easy to get lost chasing decimals of vpd. I argue for more following it more loosely and focus on just looking at the plant and what its doing. Youre not after following vpd just cause people online say you should do it; youre after the plants response to correct vpd: transpiration. Are all leaves erect with leaf boners? Your in good range. Is the plant with saggy posture and ppots take time before dry? Look up your vpd values, adjust towards them, and read your plants again

If can see how hard you infinity run your extraction on your controller or just measure the tine between rev up and down while the fan is on setting for controlling rh: the harder it has to work, the shorter the rev down cycles, the more humidity your fan is having to remove; the more the plant is transpiring. VPD is not something your following for its own purpose, you do it so that the plant sucks watter as much as it can, a great correlate to good plant performance. When you feel youre getting it just right: raise light intensity and nutes in middcycle 3-4 week, usually here, when nicely dialed in, the plant can take tremendous almost infinite light as long as your spectrum is not deficient.

Hello RS, thanks for the reply. I agree, the plants will show if VPD is good and I have found that sweet spot, where they look great, but now you suggest: 'raise light intensity'? You're saying get settings right and then change them?? You're killin' me ;-). As I am understanding, VPD is driven by deviations between ambient temps vs leaf temps and humidity. If one get any of these wrong they will look like $hit. But you are saying there should be more lag between humidity going 'on' (VPD goes down) and humidity going 'off' (VPD goes up). Sounds like good advice.

RS I'm a simple old man. The more I can eliminate in the growing cycles the happier I am.
Eliminating the HID and going to the LED, fire & high heat worries was initial change requiring higher ambient temps which changes RH%s.

I grow in PPKs (and have for years, thanks D9). The PPK, once set up, is simple.. same 2 nutrients (600PPMs throughout the grow), no nutrient changes or adjustments and not worrying about PH (I like this the best). The controller has made (after adjustments) the process even more simple. Making me aware of the symbiotic nature of temps vs RH%. Maybe I'm over thinking the whole process, but she looks great after my initial 'adjusting' adventures of VPD. If I were a newbie (to growing) I think the tent/grow packages from Vivosun or AC Infinity would be the way to become more easily acquainted to early, 'I don't know what to do' problems and more successful early grows.

I will admit though the 80F/55%RH did me great before the controller.

 

[Rocket Soul]

What im saying is that led lights are tricky, with all this environment vpd bullshit. But the brightside is, that when you have everything really dialed in there is a brightside: with good genetics theres a time in midflower where you can almost give infinite light as long as you keep up with nutes and in turn with transpiration. Going thru all that environment control stuff its a pity not to try to take advantage of this window. Try small first of course, and it might be harder to do with ppk since they are recirculating. We do drain to waste coco and dont dial down on ec runoff until 3ec in midcycle, and its given us better results but we really have to balance stuff well for flush and fade to be ok. Ymmv

I love the ppk system and looking to do a drain to waste version of this: just a tailpipe for easier draining of the pot and no pwt. More media in the pot with same watering frequency.
Do you have a grow thread to look at? Whats your media?
Im not able to score turface or cap jacks :/

 

[Rocket Soul]

But you are saying there should be more lag between humidity going 'on' (VPD goes down) and humidity going 'off' (VPD goes up). Sounds like good advice.
No not at all: i was saying in the first answer that a fan set to control for high rh can be used to measure how hard your plants are transpiring. And since this is what were after rather chasing some value in the table we can use this as another correlate to "plant reactions". Looking for physical signs of Ayokay plant is better than the actual vpd value, and once you got them transpiring well enough it can be hard to see the difference of 80% there and 100% there; thats when you have to look for more signs of trnaspiration.
You can also play with the nutes with this: if you feel that your working easier with a lower vpd just up the nutes a slight bit: as long as outside toxicity range the plant care of total nutes absorbed: more of weaker juice or less of stronger juice is somewhat indifferent to the plant, as long as it has what it needs.