Septoria, deficiency, neither, I don’t know?

[Rama777]

My first cuttings woohoo! I was reading about their preferred environment. Kind of all over the place. I decided to forego the misting ritual because I’m not always around. Also, I have my automations set for a target VPD. Anyone know if that’s an appropriate way to manage them? I just keep the VPD between .6 - 7

So the humidity is sometimes 80, sometimes down to 73 as the temperature swings. Usually mid to low 70’s with an average temp of 73. I bet the temps may drop to 70 tonight and the controller will probably take the humidity down to around 70 to compensate for the target VPD. That’s much easier than trying to keep a zeroed in temperature and humidity. Sound okay?

 

[Rama777]

The humidity in the tent gets up to 67% during lights off, for about a few hours. Is powdery mildew something that I need to worry about with such a crowded tent or is a few hours of high humidity fine until later in the game? I always have at least one air exchange per minute, plus a string breeze from the fans.

 

[Bdubs]

80/60 is a prime target for best results in veg. 1.1VPD

 

[Rama777]

Someday I may try to get that close. For now I’m around 1.5 with lights on and 1 with the lights off.

 

[Rama777]

I’m in flower now by the way ;)

I can definitely increase my lights off VPD using my radiant space heater. I’m just not sure that’s worth the electricity. Or is it? I’ve thrown a lot of money at this and I don’t mind throwing more, just want to be sure I’m not throwing it without a good reason.

And actually my VPD dips down to around 8.9 at worst, not long before the lights come on. I won’t let that happen when the plants start really making flowers. But I guess I do want to know if I’m running any risk of powdery mildew with almost 70% humidity at this stage?

 

[Bdubs]

VPD is a weird subject. What I gather from it all and put into practice is this:
-VPD ranges are desired and we know it keeps the plant doing necessary functions.
-VPD is a measurement of at what temperature and what humidity can you safely have the stomata open and the plant do it’s proper thing
-VPD is a guide but does not depict that the conditions/environment are optimal
-VPD is less important than targeted temps and humidity for quality and other reasons

I personally view VPD as a guide to use if I am deciding to run X temps, I want to stay in Y humidity. And vis Versa. It only takes Your target and gives the proper other value to adhere to to let the plant thrive at that desired target. But never a peg to quality in one specific range, that’s determined by temps and humidity chosen, and not chosen by VPD.

For me I peg humidity and control temps to stay in range.

 

[Rama777]

Yeah that’s good logic. I guess where VPD becomes THE most important variable is when it’s far too low, regardless if desired temps. I’d take a VPD of 2.5 over a .2 any day ;)

Well then so how about this which is more straightforward than VPD, is running a 65-68% humidity during the stretch phase safe to do as long as airflow is super good? I’m only really asking in terms of potential diseases.

 

[Bdubs]

The only time you need to worry about high humidity causing issues is in flower. 45-55RH early and mid flower and 35-45 in late flower (when you surely want to drop temps).

 

[Bdubs]

When your buds start to grow and especially when they start bulking, humidity should be a top concern if it is high. But I’ve seen high humidity grows turn out great. Although I don’t think it is something beginner to mess with.

 

[Captspaulding]

This is where im at atm, week seven d3 next week I’ll drop the temp a bit and dry the air some more.

 

[Bdubs]

5 hours after lights out. Days high was 73.

 

[Captspaulding]

5 hours after lights out. Days high was 73.

On point!

 

[Bdubs]

I’ll hit 66 degrees tonight as a low.

 

[Captspaulding]

I’ll hit 66 degrees tonight as a low.

That’s really nice. Get that fade rolling even harder.

 

[Bdubs]

Because things always don’t go as planned, things can swing and go out of your desired range for a period of time. But how you control it and change something to maintain a target is what matters. Notice I hit 57 lows for a few days even, I had to add heat to my lung room to balance after a cold front..yeah and I didn’t have a proper heater to run during that time of waiting for my new heater. Once I got that, set the lung room temps, I have left my fans pretty chill and don’t touch. But if temps go high, I drop lung room temps and let the fans stay at the same speed.

 

[Bdubs]

We can see that humidity runs high when temps are high. And humidity falls following a temp drop. So if you find the median of the two, you have a lot less controlling to do and those swings become less often.

 

[Bdubs]

That’s really nice. Get that fade rolling even harder.

Thank you sir. 77-65 and 50rh is legit. And I notice a consistent growth in that range. Remember like humans, your metabolism is controlled by temps and humidity and the amount of energy exerted during those temps. At 77-65 humans do very well burning fat and storing proper fats at night. 50 humidity is comfortable to us and even if on the hotter side 50 RH feels good. So do the plants.

 

[Bdubs]

With out of range swings, don’t make major adjustments. It can take my room 2-3 days to mellow out with no additional adjustments.

ie: if I have high temps and I put ling to 68, it takes 2 days for temps to mellow and keep targets. So I am patient to let what I set it at to do its work in the room. Less direct and more wait but it allows me to see the exact correlation from ling room to grow room.

 

[Bdubs]

Basically I never fight or chase, I try to offset and wait, make minor adjustments and wait. Patience is king in the grow world. Because I have next grow to make it better if it means I don’t stress this time.

 

[Captspaulding]

Basically I never fight or chase, I try to offset and wait, make minor adjustments and wait. Patience is king in the grow world. Because I have next grow to make it better if it means I don’t stress this time.

I can dig that