Heat and RH won't go lower without over heating

[Aqua Man]

You know @Madmax now that you have the tools to see the actual VPD your going to notice many growers who claim they dont bother with VPD and have great grows going on are always smack dab in the proper range of VPD.

Its a funny thing because almost everyone calculates it wrong to start with and many who start using VPD also do the same and then say it doesn’t work. All because many miss the fact you MUST take leaf temp into account.

There used to be so many problems with that so much so that was the reason i wrote that thread lol.

Honestly just do some jumping around and ask a few what there temp and humidity are then apply the general principle of leaf temps 4-5f cool for LED and 1-2f for HID and youll see every good indoor grow without issues sits right in those ranges.

Of course its not the only factor and not the end all be all but it wont take long to see it sure does eliminate a lot of problems.

I do the same as @Moe.Red set leaf temps then adjust humidity to line up for VPD. 75-77F leaf temp is ideal. 80+ you almost always see heat stress, 72 and below almost always see the start of P deficiency with purpling.

 

[Moe.Red]

I agree. Folks that have been growing a long time seem to have a sense of where they need to be without measuring anything. Reading the plants is always better than trying to reach a specific number if you have the skills. On the other hand, when things go wrong or you are just learning, VPD calculated correctly can be your best friend.

 

[Madmax]

You know @Madmax now that you have the tools to see the actual VPD your going to notice many growers who claim they dont bother with VPD and have great grows going on are always smack dab in the proper range of VPD.

Its a funny thing because almost everyone calculates it wrong to start with and many who start using VPD also do the same and then say it doesn’t work. All because many miss the fact you MUST take leaf temp into account.

There used to be so many problems with that so much so that was the reason i wrote that thread lol.

Honestly just do some jumping around and ask a few what there temp and humidity are then apply the general principle of leaf temps 4-5f cool for LED and 1-2f for HID and youll see every good indoor grow without issues sits right in those ranges.

Of course its not the only factor and not the end all be all but it wont take long to see it sure does eliminate a lot of problems.

I do the same as @Moe.Red set leaf temps then adjust humidity to line up for VPD. 75-77F leaf temp is ideal. 80+ you almost always see heat stress, 72 and below almost always see the start of P deficiency with purpling.

I am actually getting tacoeing on 2 plants out of the 6 when light 21" away and that plants showing 24.2 and isnt drinking that much..ive known i must b in the ballpark with vpd without even knowing how it works cause im getting a tad over 2p using 5x4 space.

 

[Aqua Man]

I am actually getting tacoeing on 2 plants out of the 6 when light 21" away and that plants showing 24.2 and isnt drinking that much..ive known i must b in the ballpark with vpd without even knowing how it works cause im getting a tad over 2p using 5x4 space.

Running all the same strain clone or seeds?

That could be light stress, genetics, wind. Have you checked the ppfd above that plant and others? Closer to a fan?

Sound like a specific issue to that plant other than VPD.

 

[Brenden302]

Wow, thank you all for the support!!! My grows in the basement so humidity is naturally higher, I'll keep what I'm doing now and just watch the plant they seem happy! I downloaded an app called tent buddy with a vpd calculator and I think I'll be ok!

Again wow thank you for the responses and yes I have a ton of air movement because of higher humidity, and I plan to move to winter grows and add a heater to the basement with a humidifier to control it more better

 

[Madmax]

Sorry for filling up your post Brendan .i got one more ..lol.. haha..Seeds .yes its close to a fan but the breeze isnt affecting it..i think your onto it with the ppfd as the light is closer to the wall there and maybe thats the reason .i have another strain at back at 16-20 inches and not affected and that one is drinking the best.also has the biggest buds.pic of how farvaway from light.the reason the lights away is because i get this tacoeing every grow and i think its the intensity?

 

[Dr.Green55]

I agree. Folks that have been growing a long time seem to have a sense of where they need to be without measuring anything. Reading the plants is always better than trying to reach a specific number if you have the skills. On the other hand, when things go wrong or you are just learning, VPD calculated correctly can be your best friend.

So True @Moe.Red, When us older folks started growing way back when we never had the gauges or knowledge that we have now. everything was done by sight and feel, when I go into a room now its just automatic, your senses and sight, just plan feel of the room tells you ballpark where you at, testers and gauges are secondary, good or bad hard to say lol , but the newer grower is definitely tester/gauge first.

 

[Aqua Man]

Sorry for filling up your post Brendan .i got one more ..lol.. haha..Seeds .yes its close to a fan but the breeze isnt affecting it..i think your onto it with the ppfd as the light is closer to the wall there and maybe thats the reason .i have another strain at back at 16-20 inches and not affected and that one is drinking the best.also has the biggest buds.pic of how farvaway from light.the reason the lights away is because i get this tacoeing every grow and i think its the intensity?
View attachment 1263913
View attachment 1263909

Yeah light would make sense for the symtoms… and not all genetics or even phenotypes of the same genetic handle light as well as the next.

A leaf will fold in the middle under stress for various reasons. When light stress the plant will do this to reduce light capture and as the stress increases it will try to point the petiole upwards to further reduce this. Usually light and heat stress are combined so you often see higher leaf temps when you see light stress since plants will also convert excess photons to heat.

But if your leaf temps are good and seeing that it kinda makes me think there is possibly another reason like transpiration rates and nutrients just slightly low uptake wise. Not enough for a deficiency but enough for stress. You did say its drinking less so id kinda lean to the plant just getting shy of the nutrient transport needed for the photosynthetic rate demanded.

Try feeding a higher dose to only those plants and make sure watering is looked at. If it spreads the looks for root pest as this seems like it could be a slight rootzone issue or a nutrient concentration issue.

And last possibility that genetic is just less tolerant to light in which case move the plant to the outside.

Id you do that and then the next plant there has an issue id say its a safe bet that its intensity related

 

[Madmax]

Awesome..thanks Aqua...can you b my dad ..

 

[Aqua Man]

Awesome..thanks Aqua...can you b my dad ..

Lmao you dont want that just ask my daughter. And im still trying to get @Moe.Red to adopt me so it would depend if he wanted grandchildren lol

 

[Moe.Red]

Lmao you dont want that just ask my daughter. And im still trying to get @Moe.Red to adopt me so it would depend if he wanted grandchildren lol

OK, I'll ask the wife when I get home if she wants a ready made family of stoners. She puts up with a lot of my shit, you never know!

 

[growsince79]

On my second grow, did a trellis net and now I have an portable ac unit, and a dehumidifier running in the lung room and the best I can get is 77 degrees and 58-60 rh, I've looked everywhere and the answer is all over, is this ok to just grow till the end with? Trellis net really changed my environment now running a dehumidifier and portable ac is not ideal but will do to keep it where it is pictures belowView attachment 1263851View attachment 1263852View attachment 1263853View attachment 1263854View attachment 1263856

Vent outside - problem solved.

 

[Brenden302]

Sorry for filling up your post Brendan .i got one more ..lol.. haha..Seeds .yes its close to a fan but the breeze isnt affecting it..i think your onto it with the ppfd as the light is closer to the wall there and maybe thats the reason .i have another strain at back at 16-20 inches and not affected and that one is drinking the best.also has the biggest buds.pic of how farvaway from light.the reason the lights away is because i get this tacoeing every grow and i think its the intensity?
View attachment 1263913
View attachment 1263909

Nah don't be sorry for filling up post, we're all here to help! So if my post gets you help then it's a win win for everyone!

 

[Brenden302]

Vent outside - problem solved.

My portable ac vents outside and my tent vents outside already, I believe it's the humidifier that heats the room up so the ac can't cool it fast enough, it's in a basement so the humidity is naturally higher so I have to run dehumidifier and that thing blows hot air out like crazy

 

[Moe.Red]

Vent outside - problem solved.

That wouldn't work for lots of people. If you push air outside, the negative pressure in the house will suck in air in every nook and cranny it can. Yesterday here it was 101*F. I'd be pushing 85*F air out to replace it with 101. Not a good fit and you will have interesting effects on your house AC system if you do that all the time.

 

[Aqua Man]

My portable ac vents outside and my tent vents outside already, I believe it's the humidifier that heats the room up so the ac can't cool it fast enough, it's in a basement so the humidity is naturally higher so I have to run dehumidifier and that thing blows hot air out like crazy

Ok so AC units put out nore heat than they do cooling… so you got the major contribution done right.

Now an AC will also dehumidify. So here is my suggestion to stop the fight between ac and dehumidifier.

Set you temps to about 80-82f. Warmer air holds more moisture so that in turn will lower your RH (because humidity is relative to temperature) that will lessen the demand on the dehumidifier and AC.

This should get leaf temps in a good range and you can expect a slightly lower leaf temp than typical under LED because of the airflow you have (evaporative cooling of the leaves.

Nake sure your deadbands are far enough apart so the equipment is not fighting eachother so hard.

The next question is where are your sensors placed?

 

[Brenden302]

Ok so AC units put out nore heat than they do cooling… so you got the major contribution done right.

Now an AC will also dehumidify. So here is my suggestion to stop the fight between ac and dehumidifier.

Set you temps to about 80-82f. Warmer air holds more moisture so that in turn will lower your RH (because humidity is relative to temperature) that will lessen the demand on the dehumidifier and AC.

This should get leaf temps in a good range and you can expect a slightly lower leaf temp than typical under LED because of the airflow you have (evaporative cooling of the leaves.

Nake sure your deadbands are far enough apart so the equipment is not fighting eachother so hard.

The next question is where are your sensors placed?

So you mean place my ac to 80-82?
I've tried just running the ac without a dehumidifier to bring it down to 75 degrees which it does and cools the tent down alot to about the same but the rh shoots to 75-80 without the dehumidifier running, here's a picture of them spaced out, don't mind the extra tent and junk it's a basement room!

The sensors for the dehumidifier and ac are built in if those sensors are what your talking about

 

[Aqua Man]

So you mean place my ac to 80-82?
I've tried just running the ac without a dehumidifier to bring it down to 75 degrees which it does and cools the tent down alot to about the same but the rh shoots to 75-80 without the dehumidifier running, here's a picture of them spaced out, don't mind the extra tent and junk it's a basement room!

The sensors for the dehumidifier and ac are built in if those sensors are what your talking aboutView attachment 1263942

Yeah change the AC to 80-82. You should then see the dehumidifier run a fair bit less and be more effective when it is running.

 

[Aqua Man]

Set the dehumidifier to about 60% and see how that effects the system. Then give a fulk day and post your results and we can go from there

 

[Moe.Red]

So you mean place my ac to 80-82?
I've tried just running the ac without a dehumidifier to bring it down to 75 degrees which it does and cools the tent down alot to about the same but the rh shoots to 75-80 without the dehumidifier running, here's a picture of them spaced out, don't mind the extra tent and junk it's a basement room!

The sensors for the dehumidifier and ac are built in if those sensors are what your talking aboutView attachment 1263942

I'm confused. The pic here is a different tent, and the other one at the top of the post is also in this room, correct?

I only see a single hose going from the AC to the window? Exhaust only? That does not add up to me. There should also be a drain line for condensate, maybe that's there and I can't see it?

In the grow tent, you have some sort of blower that moves air out of the tent? Maybe thru a carbon filter? I'm guessing it is at the top of the tent and we just can't see it? What are you using to control that blower assuming you have one? Do you have an inkbird or something like that which you can use to set temp, rh or both?