Cooling Lights Off Temps????

Discussion in 'Growing Marijuana Indoors' started by TUK5150, Jul 22, 2019.

  1. hey guys its been a little while since i posted as i finally got a grip of things thru the veg stage......this weekend is flip-mode time for the girls to give me.....well what i hope for some fine medicine. but i have a slight issue.....with me running my times from 6pm till 12pm the following day so 18 on 6 off, its quite hot here right now and with the sun hitting my house it heats up quite nicely in 25.5c with the lights off in the tent, now as far as im aware in flowering lights on temps should be as close to 26c as can i achieve the desired temp drop with the lights off? it isnt constant as when the sun finally goes around 8pm everything does go perfectly fine, but im still in veg so im talking my temps now are min 27.5c max 28/29c lights on and then by the time comes for the lights to go off obviously the outside air heats up for us....also heating my i am getting a cooltube to go in for my hps (600w), but i also wanted to add 2 600w leds maybe second or third week into flower considering ill be lowering my temps of my hps produced in and around my tent with the cool tube...any help or advice would be greatly appreciated.
  2. Increasing exhaust fan speed will get inside tent conditions closer to the conditions outside the tent.
    In the ridiculous case of infinite exhaust fan speed, the inside tent conditions will exactly equal the conditions outside the tent.
    Adding a top-fill, ultrasonic humidifier will help a little, because its microscopic water droplets absorb heat as they evaporate.
  3. Portable air conditioner
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  4. the outside room temps are 26degrees c anyway lol so still to hot for lights off, it is only for a couple hours until the sun goes each day, think this would cause problems with the THC and terp quality?
  5. Not if you are still in veg. They can take warm temps at night. Warm nights, or where the difference between day and night temps is less than 5°C or 6°C, tend to keep internoding pretty tight.

    You could try shifting your on/off hours to 7pm on, 1pm off. Or 8pm on, 2pm off to see if it helps control the heat a bit. Or dial it back to 16/8 for the last week or two of veg, maybe things will cool off by then.

    Either way though when it's that hot and you are running that many hours in the day, it's hard to not have a hotter couple hours on one end or the other. Add in HID and it's a headache. And if you add more lights, even LEDs, and even worse again, ones you can't dim or put their drivers outside the tent, it'll be even harder to keep cool.

    Thank god for dimmable LEDs right now. I'm facing the same issues. Outside air is 27°C right now.

    I'd consider AC if I were you, like @mollyjamila mentioned. Or do you have some way to exhaust that outer room better?
  7. As long as your temperature stays between 15-28 degrees then you're fine. There doesn't need to be any change between day and night
  8. of course there is the need for a drop in temp between night and day temps, otherwise plants wouldnt know the difference from sleep and play time other than the lighting, i do think it'll be okay a degree or so above the optimum requirements but may lose a few grams to the heat, hopefully i dont lose the quality of the final flower though thats my main worry.........
  9. i already exhaust out my tent into the attick, other than that thats the best i can do, im going to try an air cooler after the aircooled tube if that doesnt help i suppose it is what it is for this time of year, id quite like to see some stuff produced in high temps by people so i can get an idea of what to expect as a final result
  10. Of course there doesn't need a temperature drop. They know the difference because when the lights off, its dark. Where did you get the idea that they need a temperature drop? I've been growing over 20 years and always have my lights on in the night so the temperature balances out
  11. #11 hatmat, Jul 23, 2019
    Last edited: Jul 23, 2019
    I think you will be fine without but if you're set on lowering the lights off temp, get an AC, they're noisy and use a lot of electricity, and you need to have a vent for the hot air from the ac, and likely will have to craft a funneler box tent intake. I like Co2 bags specially in summer with hot lights on temps. *Edit

    Also you should do insulated/acoustic ducting with your cooltube and the ac hot air vent. I'd insulate atleast the exit side of the cooltube duct, I think it leaks quite a bit of heat back in to the grow area.
  12. ive just been told by other experienced growers and also read on some seed bank sites, i do have my lights to come on at 6pm till 12pm the day after, but with this heat wave my lights off temps are hitting 28c with nothing on!!! and thats pulling air from outside near my window, drag my vent from my window to my room and it only drops .5c, having to shove frozen ice bottles in my ducting to try cool the air a bit, lighrs on now and its 29.5 with lights dimmed to 250w and ice bottles in the ducting......need to try a cool tube and a swamp cooler for these peak times, to come on midday to cool the lights off temps and then ill restock it with ice later, other than that theres nothing i can do, cant have a portable AC because ive no where to vent the exhaust other than directly into the room heating the air even more in the room around the tent....
  13. So where is your cool tube going to vent? Can you not use that same portal for a portable AC exhaust? If it's not venting to outside, you'll have the same issue as with a portable AC recirculating and thus compounding the hot air issue.

    If you only have a single portal to outside, you can always use a T union or something similar to allow multiple exhaust sources.

    And cool tubes are only so effective even with ideal conditions. I had more heat troubles with a cool tube and a 1000W, with 5°C or colder air passing over the bulb, than I do with 3 x 600W QB-LED drivers and their panels just passive cooling to ambient air. Radiant heat still heated my tent rather quick with a cooltube and a 1000W, even in the middle of winter.
    Don't be surprised if a cooltube doesn't help as much as you hope it would, even with an ideal setup.

    This heat sucks man....I feel for you. I am just fortunate enough to live far enough north that nights are nice and cool even in summer.

  14. Dam that sounds like a lot of hassle. It was 31c where I live yesterday, I shut one of my tents off completely and let the other run on its own. It got to 27c in my home and 28 in my grow room. The tent with the light on was hitting 30c. The light was raised high and the plants are all doing perfectly fine

    Have you considered getting different lights? There are some high efficiency LEDs available now that can really help with the heat.

    You don't need a temperature drop in the night though, in fact having it as constant as possible is more desirable. Anyone who has told you there needs to be a drop is simply incorrect. If it was needed, then I would have problems from it, which I don't

  15. im going to have the cooltube setup as following...

    filter, small amount of ducting, cooltube, small amount of ducting, fan and out into the attick.

    im also going to go for it and just buy a portable AC and put it in the room where the tent is shut all the windows and vent it thru my chimney breast where an old breather vent was, just to cool the whole room in general.

    ive turned my lights down to 250w and temps are still high....the girls look more than happy if i say so myself....lovely and green and sitting nicely at the leafs.

    just going to go for the above and hope it works, rather than suck direct air from outside ill have it suckin the cooled air from the room in situ instead that should work.

    was 28c whilst i tried to sleep last night in my room, heat is crazy here atm. north.

  16. i almost did the same, i just turned my lights right down to 250w and hoped for the best. my temps was the same as yours in my room last night, girls look quite happy tbh, nice n green n leafs are sitting niely, no signs of stress other than me stressing lol.
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  17. OK. That might work. You getting rid of that AC heat is good.
    Your bill is not gonna be pleasant though, but sometimes you gotta do what you gotta do.

    If you ever get the chance, look at quantum board lighting. I am working my way thru this heat OK because of them.

    I can dial them right down 25% draw, and lower them right down to about 10" over the plants. With my therm gun I am getting readings of 29.5°C - 30.5°C off the heat sinks of my qb panels, while the ambient air is 26°C or so. Not bad at all.

    I have found when using qb lighting, even when you do have days you can't get the ambient heat down, my plants still do well. Without the radiant heat that comes with HID, the plants do just fine. While the air is warm, the leaves of the plant are still cool, and soft.

    Best of luck. Hopefully this heat pisses off soon
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