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Mister_D

Active member
Veteran
They aren't taking well to higher temps (~83-85) even with CO2. I think it has something to do with the composting soil going anaerobic at those temps. For now I'll keep it at 78 max.

It's not likely a problem with your soil. Unless you don't have adequate circulation in your room, and the temp of the soil itself is getting too high. Where's your humidity at day and night? Should be 60-70% during the light cycle, and around 50% at night, when using those temps and co2. My guess is VPD (vapor pressure deficit) is your problem. Do a little research on the subject, it's an important concept for any grower to understand.
 
It's not likely a problem with your soil. Unless you don't have adequate circulation in your room, and the temp of the soil itself is getting too high. Where's your humidity at day and night? Should be 60-70% during the light cycle, and around 50% at night, when using those temps and co2. My guess is VPD (vapor pressure deficit) is your problem. Do a little research on the subject, it's an important concept for any grower to understand.


RH stays around 60%. Thanks for the tip, you've just squashed my free time for today ;)
 
Holy crudballs -- after looking at some photos of plants with VPD issues, I really think you've hit the nail on the head. I'd rep you again but I'll have to dig around for a few more of your posts first.


I'm not sure what I'm doing wrong yet, because my numbers all seem to line up in the 'safe' ranges, but I'll do some more obsessive reading and get back to you.

Think it could be related to the fact that I don't really have different settings for day/night? I don't have a controller for it yet, and probably can't afford one until after this harvest, unless it is really going to noticeably improve this grow.


Anyway, back to reading...
 
Hmmph, could it be true that my plants will not be happy at 81*F unless the RH is 70+%? How do people complete a grow with CO2 at higher temps without mold or mildew?

When I get home from work tonight I'll be sure to get a good canopy temp measurement, which is something I haven't done yet. Instead, I've been relying on 3 thermometers placed around the room (a/c unit, dehumi, and a therm/hygrometer placed on the far wall). Maybe that will provide me some more insight.

Either way it goes, I think I'm going to be keeping the temps under 80 for this run, just to be on the safe side.
 

Mister_D

Active member
Veteran
Hmmph, could it be true that my plants will not be happy at 81*F unless the RH is 70+%? How do people complete a grow with CO2 at higher temps without mold or mildew?

When I get home from work tonight I'll be sure to get a good canopy temp measurement, which is something I haven't done yet. Instead, I've been relying on 3 thermometers placed around the room (a/c unit, dehumi, and a therm/hygrometer placed on the far wall). Maybe that will provide me some more insight.

Either way it goes, I think I'm going to be keeping the temps under 80 for this run, just to be on the safe side.

Plants will do fine at 81 and 60% humidity. This is at the canopy, not the room (very important difference). People that use high humidity successfully have LOTS of air circulation around the room, and use good hygiene to maintain a mold free area. Control over the inevitable night time humidity spikes is also paramount. Basically you create conditions where mold can't reproduce. Think about the rain forest, it's nearly 100% humidity all the time, and no mold issues. Some of the largest fastest growing plants (herb included) exist in the rain forest, it's not a coincidence :biggrin:.
 
Plants will do fine at 81 and 60% humidity. This is at the canopy, not the room (very important difference). People that use high humidity successfully have LOTS of air circulation around the room, and use good hygiene to maintain a mold free area. Control over the inevitable night time humidity spikes is also paramount. Basically you create conditions where mold can't reproduce. Think about the rain forest, it's nearly 100% humidity all the time, and no mold issues. Some of the largest fastest growing plants (herb included) exist in the rain forest, it's not a coincidence :biggrin:.

I can't begin to tell you how much time and headache you just saved me. Any more often-overlooked concepts I need to check out while you're at it? ;)

Thanks again.
 
By the way, my canopy temp was 5 degrees higher than the temp on the wall, and 4 degrees higher than what my a/c said. I don't know why I've never had issues with this in the past because I've always measured temp this way -- and these hoods run cooler than anything else I've ever used. That explains why they started having trouble when I set my a/c higher than 82. I feel like a dolt.
 

Mister_D

Active member
Veteran
I can't begin to tell you how much time and headache you just saved me. Any more often-overlooked concepts I need to check out while you're at it? ;)

Thanks again.

There are tons of overlooked concepts, just depends on the person as to which are over looked ;). Best advice I can give you is to read, read, and read some more. Start by clicking the "ratings" button at the top of right of each subforum. This will arrange all the threads in that sub forum by star rating. Read all the 5 star threads, then the 4 star and so on for each sub forum. This will take you probably a year or more, but the knowledge gained will be priceless :biggrin:

By the way, my canopy temp was 5 degrees higher than the temp on the wall, and 4 degrees higher than what my a/c said. I don't know why I've never had issues with this in the past because I've always measured temp this way -- and these hoods run cooler than anything else I've ever used. That explains why they started having trouble when I set my a/c higher than 82. I feel like a dolt.

We all miss little things here and there, and if ya don't know any better....... Well ya can't be expected to fix a problem if ya don't know what it is now can ya? Live, learn, then overcome :biggrin:.

BTW what's a dolt? Never heard that one before.
 

Mister_D

Active member
Veteran
I've had the same temp issues. High humidity and lots of air circulation ftw... Idk about the rainforest analogy but I'm not here to nit-pick today. :)

Didn't see any of those 20+ft monsters out in the jungle while you were down in South America :moon:? Missed one of the finer points of visiting that part of the world bobble :biggrin:
 
There are tons of overlooked concepts, just depends on the person as to which are over looked ;). Best advice I can give you is to read, read, and read some more. Start by clicking the "ratings" button at the top of right of each subforum. This will arrange all the threads in that sub forum by star rating. Read all the 5 star threads, then the 4 star and so on for each sub forum. This will take you probably a year or more, but the knowledge gained will be priceless :biggrin:



We all miss little things here and there, and if ya don't know any better....... Well ya can't be expected to fix a problem if ya don't know what it is now can ya? Live, learn, then overcome :biggrin:.

BTW what's a dolt? Never heard that one before.


dolt
dōlt
noun
1.
a stupid person.



Funny thing is, I was pretty sure I had done that already sometime over the last 10 years...Always something...
 

EllieGrows

Active member
Veteran
Have you positively identified the bugs on your sticky strips? Looks like there are many many many of them. If its fungus gnats i suggest getting some BTI going quick or your flowers will be covered. If its something worse you better really get going on the problem.
 
Now, I know that the plants will continue to bud out fine, but will the leaf damage/curl that's been done ever be repaired, assuming I am keeping my VPD at .9?
 

bobblehead

Active member
Veteran
Las Cataratas de Iguazu/Iguazu Falls- been here 3x on 2 trips.
heaven-on-earth-iguazu-falls-argentina-brazil.jpg


Maccu Picchu- been here once. I'd love to go back.
Machu-Picchu-Peru.jpg


The jungle is at the bottom of this road.
Zigzag_road_to_Machu_Picchu.jpg






Under the trees there's hardly any air movement. Its humid, and there's lots of mold on decaying plant matter. Up in the canopy is where most of the life is, along with more air circulation... But the sun and the starches it helps produce are what stop the mold from growing. BRIX.

My garden outside is only getting 2hs of direct sunlight a day b/c of the Earth moving in relation to the Sun and the shadows being cast by all the trees... My tomato plants are molding and dying.

I mean I guess the rainforest analogy works... but imo you made it sound like there isn't mold in the jungle. Its everywhere. Its what kills the weak plants and feeds the stronger living stuff.
 
Have you positively identified the bugs on your sticky strips? Looks like there are many many many of them. If its fungus gnats i suggest getting some BTI going quick or your flowers will be covered. If its something worse you better really get going on the problem.

It's fungus gnats. I've been "keeping an eye on them" so far, but you're absolutely right. Observe-and-report is over. It's time to deal with them.
 
I've decided that I'm going to put my dehumi on a timer, and only let it run during lights off. I'll set it to 50%. I may have to get a humidifier for lights on. I was assuming that I didn't, since my room is sealed and I'm running co2, but maybe I had some misconceptions there. We'll see what it looks like tonight.
 
Aw crap. I just found the manual for my dehumidifier online. Turns out it has a built-in cycle timer, which is good. But it looks like the mode I had it set to, "Auto", automatically sets RH to 50%. Bad, bad, bad, bad, bad. I wonder why it even displays the set RH on the screen, that's very misleading. At least I know now.
 
I picked up some mosquito dunks and a green CFL at the lowes. Tonight I'll spend some more time monitoring my environmental factors and deciding if I need a fogger or if I need to steal the girlfriend's bedroom humidifier
 
Freaking hell man, there is a LOT of misinformation on the topic of temperature and humidity out there. No wonder I had it wrong. 9 out of 10 closed threads settle on some variation of "50-60% rh for veg, 40 - 50% for flowering." Now I realize that that's just some bull.

A lot of the tops closest to the lights have been hit pretty hard. Some of the plants just look scraggly now too. I really hope their appearance can bounce back now that their environment is a little more hospitable. I'm sure my yield will be affected, but not nearly enough to scrap the grow. Bud development still looks on pace throughout the room.


I think I need a humidifier in the room. I'm going to try running my tea brewer with clean water only to raise RH in lieu of a humidifier. If it works, I may stick with it throughout the grow. I'm really hoping to avoid buying a controller. Any thoughts?
 

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