whitewidow2
Well-Known Member
Hi, with all this talk of day time temps. - what are the ideal night temps both for veg and humidity Thanks
Night time temps and humidity?.... *info needed*
- Thread starter whitewidow2
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Waterpeace13
Well-Known Member
At least 10 degrees cooler than day temps and I think not below 60F.
whitewidow2
Well-Known Member
I have heard this too... 5-10 degrees cooler But what about the humidity levels? Should it just relate accordingly to the drop ie raise or lower it a bit or should you use a humidifier to keep it at a cetain level The reason i ask is that if i use my humidifier in my tent it can help to lower my daytime temps even with the air cooling - but im just concerned about the humidity levels at night Daytime - Veg 60% and for Flower 30-40% But what about night - time humidity? Thx
whitewidow2
Well-Known Member
I read some where that the humidity should be between 40 and 60 at all times? Does night time humidity matter that much or will it just adjust with the temperature drop? Thx
trichomedome
Active Member
Early flower you get away with higher r.h 70/80% but it encourages elongation when there in full flwr you dont want the r.h above 55% 60% max,"bud rott" the temp should not fall bellow 20/21c at lights out "idealy" otherwise the roots have trouble taking up nutes, leading to deficiancies. If your in the uk and dont use a heater you,ll have noticed your leaf stems and viens going redish recently ? if yes then it,s caused by the cold. 
Imo Run your lights through the night when its coldest it,s easyer to cool "namely in summer" and easyer to heat through the day, if your in a house then you have heating all day when the light is of it,s win win situation. atb TCD 
"surely there,s someone else that lights them through the night"
unless there,s some obvious reason for daytime runing that i,m missing ???
Imo Run your lights through the night when its coldest it,s easyer to cool "namely in summer" and easyer to heat through the day, if your in a house then you have heating all day when the light is of it,s win win situation. atb TCD "surely there,s someone else that lights them through the night"unless there,s some obvious reason for daytime runing that i,m missing ???
whitewidow2
Well-Known Member
Ok cool, im running veg just now 18/6 lights on at 0600 lights off 00.00 My max/min hygrometer measured: 77.1F MAX 49% MAX 61.3F MIN 34% MIN This was all without the use of a humidifier or dehumidifier Do these seem ok or is there something that can be done about them How important are night temps and what is going on while your babies are sleeping?
whitewidow2
Well-Known Member
does anyone have the ideal night - time temps and humidity for both flower and veg?
Alex Erick
New Member
Is there any way I can revive this thread? I'm new to growing and I see you've posted this a long time ago, is there anyway some one could tell me how important night time temps and humidity are? Especially during seedling to veg!
Thank you so much
Thank you so much
ANC
Well-Known Member
It depends. are you fighting stretching, then night temps may be higher than day temps.
If you can gradually increase brightness in the "morning" and gradually dim it at "night", you will counter humidity spikes. As the room cools down.
Have a heater and a cooler and a controller to run them automatically. Don't let it swing where it wants to.
If you can gradually increase brightness in the "morning" and gradually dim it at "night", you will counter humidity spikes. As the room cools down.
Have a heater and a cooler and a controller to run them automatically. Don't let it swing where it wants to.
SchmoeJoe
Well-Known Member
Humidity should be kept in the same ideal range, day and night, depending on the phase of growth. For veg growth the important thing to understand is vapor pressure deficit or VDP. Basically the weight of the water in the air affects a plants abity to transpire or breath . Higher humidity means more weight in the air that the plant has to push against to transpire. Lower humidity is less resistance and the plant can basically breath easier. In veg a smaller plant with a small root system and smaller total leaf surface area can't transpire as much as a larger plant so a somewhat higher humidity is better. As the vegging plant gets bigger the ideal humidity gets a lower. You don't have to get too carried away with keeping humidity exactly perfect, especially in veg. The best thing is to keep the humidity toward the drier side of the ideal range, at least for established plants, because the better they can transpire the more water they can uptake which will translate to faster growth if everything else is dialed in. For flowering plants keeping toward the drier end of the range is crucial for preventing mold but it can also increase resin production making for more cannabinoids and terpenes.
As for temperature the usuall practice is to focus on keeping the night time temp from getting to low because it slows growth and raises humidity which can also slow growth but is also the #1 cause of bud mold. Dropping the temp low the last week or two as long as you can control the humidity is a popular way to bring out colors too though. On the other end night temps that are higher than your day time temps can be used to manipulate growth. Just like VDP it's not something that you should be really worried about having absolute control over but it's a good thing to understand. The higher night temp is called a positive dif. Just like the VDP temperature differential is something that isn't too complicated but even compared to how much I've already typed out here it's more info than I want to try to post here. There are good articles on both that you can find that do a good job of explaining it.
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Budley Doright
Well-Known Member
Why drop temps at all? Would it not be better to maintain the same temps and keep VPD at the same number, lights on, lights off? What is the advantage of lowering temps?
Budley Doright
Well-Known Member
I was referring to following the VPD and trying to keep a spread, just seems like a whole pile of headaches lol. I only lower temps for the simple reason that it cost more to heat at lights out so I drop the temps, the humidity rises but I'm not to concerned as moisture content stays pretty much the same.
SchmoeJoe
Well-Known Member
Humidity is relative (HR). It isn't the actual amount of water in the air that affects the plants but it's ratio to the temp or HR. As far as VPD I did say that isn't so important that you follow it strictly but that if you want to understand how humidity affects the plants studying VDP is where it's at.
Budley Doright
Well-Known Member
I realize it is a percentage of the amount of moisture that the air is able to hold at that temp, note I said moisture content stays pretty much the same. That is why I think it may be better to actually keep temps and humidity the same and actually follow VPD. I have studied VPD and draw my conclusions from that.
NugHeuser
Well-Known Member
Okay so me for example, where I live it's getting real cold. I'm on my second grow at day 34 of flower, room temps are getting down to low 60s with rh of right around 30s. I currently don't have a space heater either, how much of a big deal is it for temps to be dropping to low 60s?
If it's a pretty big deal I can go buy one, I'm just wondering, is it really that big of a deal?
If it's a pretty big deal I can go buy one, I'm just wondering, is it really that big of a deal?
Budley Doright
Well-Known Member
I let my room get down to mid 60's with out a noticeable slowdown but I don't let it get much below 65 then the heater comes on
. I keep res temps at 66-67 as well. My canopy temps are 75-78 lights on and humidity is kept at 45-55 at all times using intake to dry and humidifier to add back. I have also allowed humidity to get pretty high in flower at times and never had mould or PM inside. Good air flow I think is the key to that 
.
NugHeuser
Well-Known Member
Yeah my highs get into the upper 70s during lights on.I let my room get down to mid 60's with out a noticeable slowdown but I don't let it get much below 65 then the heater comes on
The room is 9.5x9 and canopy is 9.5x4.
For fans I have a 6" inline fan intake connected to a duct splitter and 2 ducts with adjustable registers on them blowing over top of the lights/canopy. An 8" inline exhaust fan attached to a carbon filter. A smaller oscillating fan blowing under the canopy, a bigger oscillating fan blowing over the canopy, and a floor fan blowing upward at an extremely large bushy plant that I have because I'm worried it may get pm or mold as bushy as it is
NugHeuser
Well-Known Member
I found two small spots on two leaves right next to each other on my bigger plant, I'm worried that it was pm. But I looked over the rest of the canopy and didn't find anything, and haven't seen anymore since finding it a few days ago.
Can pm really form with all that air movement with rh down around 30 percent?
I was drilling a few holes where I had to lean over the canopy about a week and a half ago so maybe it was just drywall?
Can pm really form with all that air movement with rh down around 30 percent?
I was drilling a few holes where I had to lean over the canopy about a week and a half ago so maybe it was just drywall?
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SchmoeJoe
Well-Known Member
I misunderstood. Your comment about the headaches made me think you were leaning the other way. Look into temperature differential. It affects growth in important ways.