Need Help with Lowering Grow Room Temperature

whitewidow2

whitewidow2

Well-Known Member
Ok so i got my 250w hps... fitted it up the other day and have started flowering just two plants, ive only recently got a temp gauge and humidity gauge as well so im now starting to take note of humidity and temps etc.

Humidity seems to be ok, but temps seems to be about 80 but can reach up to 90F

Any ideas how i can solve this.... heres some pics of my setup











thanks guys.
 
whitewidow2

whitewidow2

Well-Known Member
I did all the calculations and worked out i had to move 23m3 per hour (allowing for inefficiencies caused by ducting and carbon filter) and my fan moves 145m3 per hour so technically everything should be fine - yet it isnt...

Do you think its got anything to do with the filter size? Help lol
 
S

sedate

Member
I did all the calculations and worked out i had to move 23m3 per hour (allowing for inefficiencies caused by ducting and carbon filter) and my fan moves 145m3 per hour so technically everything should be fine - yet it isnt...
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What are "the calculations?"

Just looking at your pictures, methinks you didn't calculate for the fact that you are reusing ambient air that has already been heated and scrubbed - hence your heat build up. You must run your exhaust outside if you want those "calculations" to function as intended.

Anyway - occasional temp spikes up to 90 and even 100 are OK for brief periods - recall the tremendous outdoor cannabis production possible in tropic zones. I know a guy that runs a dispensary here in Colorado that keeps his Durban Poisons at 93F on purpose - his yeilds and buds are freaking huge. In many respects here, air movement is as important or more than ambient air temperature.

Eitherway, 80F is ideal for cannabis (I prefer 81 - 85 over the traditional 76 - 78F recommendation) and your plants look REALLY nice. I dunno what you're worried about.
 
I

Illegal Smile

Guest
What's the ambient temp in the room? You can exhaust all the air you want but if the replacement air is still too warm it won't help much. You may need to get AC going to cool it.
 
whitewidow2

whitewidow2

Well-Known Member
I worked out my calculations according to a formula on a grow forum from one of the big growing suppliers over here... if you want to check it out its at www.progrow.co.uk > forums > faq > environment/ventilation it will tell you everything there - however even with this methodolgy the temps are still a bit high - im just worried it will affect growth or cause problems as i heard ideal temp is about 75F with a humidity of 50-60%
 
whitewidow2

whitewidow2

Well-Known Member
Illegal Smile said:
What's the ambient temp in the room? You can exhaust all the air you want but if the replacement air is still too warm it won't help much. You may need to get AC going to cool it.
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I have no idea man - i havent checked, the reason im not venting to outside the house is to avoid detection, the warm air just blows back into the room under the cupboard - would opening a window help?
 
whitewidow2

whitewidow2

Well-Known Member
Ok ive just opened up a window in the same room so hopefully that will help... can already feel the room is a lot colder and with us coming into winter and the air being cool hopefully this will solve things.
 
talon90

talon90

Active Member
thats what i had to do cracked a window and droped temps dramaticaly that should do it if not i agree with sedate get some outside air in
 
S

sedate

Member
whitewidow2 said:
I have no idea man - i havent checked, the reason im not venting to outside the house is to avoid detection, the warm air just blows back into the room under the cupboard - would opening a window help?
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Well yea of course it would - but if detection is a serious risk for you then you would probably be better off with hotter plants than prison. I'm tellin man - temp spikes to 90 are not going to hurt them - 90 degrees happens everywhere in nature all the time in the natural range of cannabis during the growing season. This isn't bad unless it last for hours and hours or days. Spiking there at 3pm is not critical.

What I would do is build a *very* aggressive carbon scrubber inline with your exhaust and see if you can't just vent straight outside - run the thing to vent out next to ur window and then run those dual window fans on the 'exhaust' setting.

Here:

http://www.progrow.co.uk/acatalog/carbon_filters_silencers.html
 
doitinthewoods

doitinthewoods

Well-Known Member
sedate said:
Well yea of course it would - but if detection is a serious risk for you then you would probably be better off with hotter plants than prison. I'm tellin man - temp spikes to 90 are not going to hurt them - 90 degrees happens everywhere in nature all the time during the natural range of cannabis.

What I would do is build a *very* aggressive carbon scrubber inline with your exhaust and see if you can't just vent straight outside - the the thing to ur window and then run those dual window fans on the 'exhaust' setting.

Here:

http://www.progrow.co.uk/acatalog/carbon_filters_silencers.html
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" temp spikes to 90 are not going to hurt them - 90 degrees happens everywhere in nature all the time during the natural range of cannabis."

Nothing about growing indoors is "natural". Outside, yea it's natural, it also has the sun, and a breeze, and plenty of air, and rain. You have to provide the elements.

You need a better exaust fan.
 
OGKush00

OGKush00

Active Member
Have you though about removing the Ballast from the room? prolly shed a couple degrees right there... I would leave the door cracked a bit allowing for better ventilation, you aren't getting enough cool air in... :leaf:
 
S

sedate

Member
Okay I read through that progrow FAQ here:

http://www.progrow.co.uk/forum/viewtopic.php?f=20&t=60

That's a good FAQ - really accurate for cannabis.

Anyway - they don't spell it out but I believe it is not only implicit but rather necessary for a grow room to function as they describe without outside ventilation - I guess the FAQ should be stated that explicitly, but for the forumla's to work the way that the FAQ states one would require ventilation outside the growroom. "behind the cupboard" isn't going to cut it man.
 
S

sedate

Member
doitinthewoods said:
Nothing about growing indoors is "natural". Outside, yea it's natural, it also has the sun, and a breeze, and plenty of air, and rain. You have to provide the elements.
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What? Are you talking about?

This is moronic bitchiness at best -

Growing indoors is an attempt to provide a perfect natural environment. So while the outside might have sun, breeze, air, and rain - indoors has an HPS bulb, a fan, and a guy with a watering can. So I have no idea what in the world your point is.

The idea that the plant will react to higher temperatures in one environment while NOT reacting to them in one that provides all the same "elements" is obviously wrong.

Now,

doitinthewoods said:
You need a better exaust fan.
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This is also wrong. He's already well invested in ventilation, and if you bothered to read the entire thread other than the part you thought you could smarmly disagree with, you'd see that not only do his plants look excellent, but he's moving plenty of air. Beating a plant to death with wind is a good way to damage it. Brief temperature spikes to 90F might slow down rapid growth a bit for some strains, but it won't cause any permanent problems.

So, as I said, if he really feels this is a critical concern - which I don't think it is but some ppl are nuts about their plants - then he needs outside ventilation - even if it is just ventilation to the rest of his residence.

Lastly, the OP's concern is detection, and temperature spikes are better than prison.
 
tom__420

tom__420

Well-Known Member
sedate said:
What? Are you talking about?

This is moronic bitchiness at best -

Growing indoors is an attempt to provide a perfect natural environment. So while the outside might have sun, breeze, air, and rain - indoors has an HPS bulb, a fan, and a guy with a watering can. So I have no idea what in the world your point is.

The idea that the plant will react to higher temperatures in one environment while NOT reacting to them in one that provides all the same "elements" is obviously wrong.

Now,



This is also wrong. He's already well invested in ventilation, and if you bothered to read the entire thread other than the part you thought you could smarmly disagree with, you'd see that not only do his plants look excellent, but he's moving plenty of air. Beating a plant to death with wind is a good way to damage it. Brief temperature spikes to 90F might slow down rapid growth a bit for some strains, but it won't cause any permanent problems.

So, as I said, if he really feels this is a critical concern - which I don't think it is but some ppl are nuts about their plants - then he needs outside ventilation - even if it is just ventilation to the rest of his residence.

Lastly, the OP's concern is detection, and temperature spikes are better than prison.
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I don't know who you are but you have a real cocky vibe to you
How is a stronger exhaust fan going to as you put it "beat a plant to death with wind"?
Care to explain that? Temps of 90°F is too high
Yes the ops plants look good but if the temps were better the plants too would look better
If the temps are high you have two options
Higher exhaust fan, or move your passive intake duct to a cooler spot such us under your house or connected to a window to bring in cool fresh air
You seem to want to point out that other people are wrong yet you offer no useful information to the op on his temp problem
 
whitewidow2

whitewidow2

Well-Known Member
Thanks tom and thanks to everyone who has commented...

This is my first attempt with hps and only day one of flowering - i was using cfl's before so i wasnt sure what to expect, i did as much reading up as i could beforehand but we all know that heat is one of the biggest problems the indoor gardener faces. For now im going to keep my window open so that i can get lots of fresh air into the room to lower the ambient temperature outside the cupboard and to give me fresher cleaner air in through the passive intake. Im now wondering if i should maybe upgrade the extraction fan, the temps sit about 80-85 at the moment to give you an idea of whats happening.
 
whitewidow2

whitewidow2

Well-Known Member
OGKush00 said:
Have you though about removing the Ballast from the room? prolly shed a couple degrees right there... I would leave the door cracked a bit allowing for better ventilation, you aren't getting enough cool air in... :leaf:
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This is also a good plan ogkush... will try this tomorrow and report back if it makes any difference, it is a maxibright ballast and whilst silent in operation they can get a bit hot.
 
tom__420

tom__420

Well-Known Member
Your fan is not strong enough, it works out to only like 85 CFM and I had to use 306 CFM to cool my 250 watt HPS that was air cooled too
I would look into a stronger inline fan and then maybe you could use your current exhaust fan as an intake fan or maybe vent out a veg room
 
S

sedate

Member
tom_420 said:
I don't know who you are but you have a real cocky vibe to you
Click to expand...
Well isn't that the point of the internet?

tom said:
How is a stronger exhaust fan going to as you put it "beat a plant to death with wind"?
Click to expand...
Because I've read the whole thread, I know that he's well invested in ventilation - we covered that in the first page of posts.

tom said:
How is a stronger exhaust fan going to as you put it "beat a plant to death with wind"?
Care to explain that? Temps of 90°F is too high
Yes the ops plants look good but if the temps were better the plants too would look better
If the temps are high you have two options
Higher exhaust fan, or move your passive intake duct to a cooler spot such us under your house or connected to a window to bring in cool fresh air
You seem to want to point out that other people are wrong yet you offer no useful information to the op on his temp problem
Click to expand...
In fact I provided a solution that takes into account the OP's installation and growing concerns. You have not.

And since I've read the whole thread, unlike you, I know that his problem is not exhaust veliocity, but the fact that he's venting back into his grow room. So he'll stay at 90F no matter how much windspeed he picks up.

Furthermore, he's only spiking at 90, he's not really there all the time (I know that because I've read the whole thread) - he's down at 80 which is perfectly workable for cannabis.

Adding wind without ventilation will not help the OP, okay Tom?

Re-read the entire thread before you complain about other ppl's good advice.
 
greenyield

greenyield

Well-Known Member
sedate said:
[/COLOR]

What are "the calculations?"

Just looking at your pictures, methinks you didn't calculate for the fact that you are reusing ambient air that has already been heated and scrubbed - hence your heat build up. You must run your exhaust outside if you want those "calculations" to function as intended.

Anyway - occasional temp spikes up to 90 and even 100 are OK for brief periods - recall the tremendous outdoor cannabis production possible in tropic zones. I know a guy that runs a dispensary here in Colorado that keeps his Durban Poisons at 93F on purpose - his yeilds and buds are freaking huge. In many respects here, air movement is as important or more than ambient air temperature.

Eitherway, 80F is ideal for cannabis (I prefer 81 - 85 over the traditional 76 - 78F recommendation) and your plants look REALLY nice. I dunno what you're worried about.
Click to expand...
i have to agree with you on 85f, the plants seem to love the heat and ive even hit 94f through the summer and the tops swelled up like they were on steroids, they were like 12" long 3" to 3.5" diameter.

i checked them every day expecting to see some hermies but they were fine although it did take a week extra to ripen, probably due to the stress but it was worth it.

it all depends what strain you are using and i know that most growers like to keep it at around 25 celsius but i like it warm.

if you run a room at or slightly above 90f you can use co2 and you wont have to cool the room then as the plants thrive on co2 in hot temp. :fire:
 
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