Temperatures, fact or fiction?

anybody have success in the attic? temps go hot to cold, from day to night.

McGruppsMonsters said:

Anything over 85 degrees without question not only decreases yield but also potency of the herb. You can push a bit higher if you are burning c02 as someone already said, but I try to keep things in the canopy under 85. I read 76-79 degrees is the temp in which photosynthesis is conducted the easiest and most effeciently. good luck

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Without questions, and how do you base this "fact". I can't see how anyone on this site could really prove it without doing a test.

However, there are 3 different types of strain when it comes to temperature. Indoor plants outdoor plants and greenhouse plants. Indoor plants can be grown outdoors but only where the temperature is hot. greenhouse plants are like a mid way and outdoor prefer cooler temperatures. So if these indoor strains prefer to be grown in hotter temperatures and this is something I have picked up from sensi seeds then the old way of 85 or lower isn't entirely correct.

I know what the situation is like for seeds and whatever in the states, so i think I will go with the dutch.

As long as your not burning the plant how can you be doing wrong if you have good air circulation. Please bare in mind though that most things you have read have also been by written by Americans.

Why does fdd claim that is outdoor is so much better than any indoor, the guy lives in cali where temperatures match my grow room. So you have still failed to convince me, even to judge by my own grow room and how they are doing, I would not say that the heat is holding them back any.

nongreenthumb said:

Without questions, and how do you base this "fact". I can't see how anyone on this site could really prove it without doing a test.

However, there are 3 different types of strain when it comes to temperature. Indoor plants outdoor plants and greenhouse plants. Indoor plants can be grown outdoors but only where the temperature is hot. greenhouse plants are like a mid way and outdoor prefer cooler temperatures. So if these indoor strains prefer to be grown in hotter temperatures and this is something I have picked up from sensi seeds then the old way of 85 or lower isn't entirely correct.

I know what the situation is like for seeds and whatever in the states, so i think I will go with the dutch.

As long as your not burning the plant how can you be doing wrong if you have good air circulation. Please bare in mind though that most things you have read have also been by written by Americans.

Why does fdd claim that is outdoor is so much better than any indoor, the guy lives in cali where temperatures match my grow room. So you have still failed to convince me, even to judge by my own grow room and how they are doing, I would not say that the heat is holding them back any.

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Are you comparing outdoor to indoor? Your temp may be similar to temps outside some days, but it's not the same conditions. The temp outside is cooler in the morning, it's peek in the afternoon and starts cooling off again in the evening. Clouds? Also we have spring/summer/fall. So it's not a scorcher outside all day everyday. How much fresh air Co2 do plants get outside compared to 80 plants stuffed in your basement? In your grow room your going to have basically the same conditions day after day where as outside there are many variables. Some bad some good, i could go on and on but my fingers hurt and i'm too stoned. I know that you know your shit bro and probably know more then me when it comes to MJ. I hate to say this, i think it will catch up with you but i know you want to prove us all wrong so if your willing to try... We all would like to save on the cost of those expensive high cfm exhaust/intake fans. Only 6 - 7 more weeks to go, keep us posted.

MajoR_TokE said:

Are you comparing outdoor to indoor?

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Both are very different I am aware.

MajoR_TokE said:

Your temp may be similar to temps outside some days, but it's not the same conditions.

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No they are not the same conditions but doesn't any indoor grower strive to mimic the outdoor conditions.

MajoR_TokE said:

The temp outside is cooler in the morning, it's peek in the afternoon and starts cooling off again in the evening.

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I have my flowering room run the lights through the night, they turn on at around 9pm and turn back off again at 9am. During the dark period the temperatures drop to around 75, which is actually my daytime. During their light period, my sleep time, the temperature obviously starts off at 75 and gradually increases up to 98 (this was the max last night) and then drops back down again to around 88 when its really cold in the night and gradually drops back down to when its 9am when the lights go off.

MajoR_TokE said:

Clouds? Also we have spring/summer/fall. So it's not a scorcher outside all day everyday. How much fresh air Co2 do plants get outside compared to 80 plants stuffed in your basement? In your grow room your going to have basically the same conditions day after day where as outside there are many variables. Some bad some good, i could go on and on but my fingers hurt and i'm too stoned.

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During the night when the lights are on the basement, the door to the basement is left open, so that is a flow of air. So during this time, new air is being allowed in, ( i have no extractor fan though.

Plant habit is that during the day they breath in co2 and breath out oxygen. Which is what keeps us alive on this planet. During the night cycle though, it actually reverses and the breath in oxygen and breath out co2.

I'm not too worried so far, I haven't had an extractor fan in all my grows to date and haven't noticed a low yield. I'm not by any means saying that this is the way to grow, all i'm trying to do is say that if you got high heats but the plant is dealing with it, it isn't necessarily a bad thing. My last harvest was as strong as and the plants yielded well too, so I have no complaints. I'm sure that adding co2 will dramatically improve growth and its something i plan to do in the not to distant future.


I know that you know your shit bro and probably know more then me when it comes to marijuana. I hate to say this, i think it will catch up with you but i know you want to prove us all wrong so if your willing to try... We all would like to save on the cost of those expensive high cfm exhaust/intake fans. Only 6 - 7 more weeks to go, keep us posted.

As an indoor grower I do my best not to mimic the outside as the point of growing inside is so you dont have to deal with all the issues outside and mother nature cause. I personally as an indoor grower try to perfect the growing enviromnet by trial and error and see what effects plants both good and bad then tune it in to perfection which cant be done outside.

hmmmm this is an interesting topic so is it really a factor fiction?hehe

I didn't read the whole thread so I'm not sure if this was mentioned or not, but I read a Doctors thesis about 3 years ago that claimed THC actually acts as a sun screen to the plant and also acted like a sorta anti-freeze. I just read in the advanced cultivation part of this forum that stressing a plant during budding can cause a larger production of THC. It was under the Ultra Violet Light thread. . . In this case you may find that higher temperatures during flowering will cause an increase in the THC content of the plant. I personally think the quality of whats in the air will effect the plants health more then the temperature, but it wouldn't be a bad test to run if you have the time and space.

Could be big problems if spider mites found their their way into a hot dry room like that. The reproduction rate would be insane if they ever got a foothold.

I've grown a clone from the same plant as a friend with a very hot room. I ended up with dense nuggets while his made a looser, spiky looking bud with little floral clusters popping off everywhere. Nice and cool is my preference, but my humidity will also spike at lights-off if I let it get too warm.

The other thing to watch out for with the higher temperatures is the material you are using in your grow rooms. Sure weed can handle hot temperatures, but there are no such things as PVC plastics in the Hindu Kush region which have a limit to the temperatures they can endure. A lot of PVC plastics like pandaform and other brand liners have been tested up to 95f and therefore are deemed safe up to those temps, but any higher and you risk leeching out toxic gasses which will damage your plants.

Let me tell you from experience if you get a single spider mite in that room running temps over 90 degrees F, you are going to see an absolute explosion of reproduction that you WON'T be able to control.

Where as if you figure out a way to keep your room cooler, you can try to control the mites. It's just really hard to keep up with them when they are reproducing that fast.

my ghetto grow case is at 76 degrees farenheit, 52% relative humidity, seedlings are very healthy looking. when the lights are off for 4 hours the temp drops to 60-65. they seem to be thriving, using 2 23 watt cfl's. just vegging until i can get em outside at the end of april!!!