Question what is the max tempeture for growing indoor ?
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Slipon
Well-Known Member
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[TD="width: 100%"][h=1]TEMPERATURE - Cannabis Growing Guide[/h]Proper temperature is one highly variable factor. Most books state optimum grow temperature to be 70-80 degrees, but many list extenuating circumstances that allow temperatures to go higher. Assuming genetics is not a factor, plants seem to be able to absorb more light at higher temps, perhaps up to 90 degrees. High light and CO2 levels could make this go as high as 95 degrees for increased growth speed.* An optimum of 95 degrees is new data that assumes very-high light, CO2 enrichment of 1500 ppm and good regular venting to keep humidity down. It is not clear if these temperature will reduce potency in flowers. It may be a good idea to reduce temperatures once flowering has started, to preserve potency, even if it does reduce growth speed. But higher temperatures will make plants grow vegetatively much faster, by exciting the plants metabolism, assuming the required levels of CO2 and light are available, and humidity is not allowed to get too high.
With normal levels of CO2, in a well vented space, 90 degrees would seem to be the absolute max, while 85 may be closer to optimum, even with a great deal of light available. Do not let the room temperature get over 35 C (95 F) as this hurts growth. Optimal temperature is 27-30 C (80-86 F) if you have strong light with no CO2 enrichment. Less than 21 C (70 F) is too cold for good growth.
Low temperatures at night are OK down to about 60 degrees outdoors, then start to effect the growth in a big way. Mid 50s will cause mild shock and 40s will kill your plants with repeated exposure. Keep your plants warm, especially the roots. Elevate pots if you think the ground is sucking the heat out of the roots. This is an issue if you have a slab or other type of cold floor.
As temperature goes up, so does the ability of the air to hold water, thus reducing humidity, so a higher average temperature should reduce risk of fungus.
Contrary to many reports, high humidity is not good for plants except during germination and rooting. Lower humidity levels help the plant transpire CO2 and reduce risk of molds during flowering.
Studies indicate the potency of buds goes down as the temperature goes up, so it is important to see that the plants do not get too hot during flowering cycles.
* D. Gold: CO2, Temperature and Humidity, 1991 Edited by E. Rosenthal.
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[TD="width: 100%"][h=1]TEMPERATURE - Cannabis Growing Guide[/h]Proper temperature is one highly variable factor. Most books state optimum grow temperature to be 70-80 degrees, but many list extenuating circumstances that allow temperatures to go higher. Assuming genetics is not a factor, plants seem to be able to absorb more light at higher temps, perhaps up to 90 degrees. High light and CO2 levels could make this go as high as 95 degrees for increased growth speed.* An optimum of 95 degrees is new data that assumes very-high light, CO2 enrichment of 1500 ppm and good regular venting to keep humidity down. It is not clear if these temperature will reduce potency in flowers. It may be a good idea to reduce temperatures once flowering has started, to preserve potency, even if it does reduce growth speed. But higher temperatures will make plants grow vegetatively much faster, by exciting the plants metabolism, assuming the required levels of CO2 and light are available, and humidity is not allowed to get too high.
With normal levels of CO2, in a well vented space, 90 degrees would seem to be the absolute max, while 85 may be closer to optimum, even with a great deal of light available. Do not let the room temperature get over 35 C (95 F) as this hurts growth. Optimal temperature is 27-30 C (80-86 F) if you have strong light with no CO2 enrichment. Less than 21 C (70 F) is too cold for good growth.
Low temperatures at night are OK down to about 60 degrees outdoors, then start to effect the growth in a big way. Mid 50s will cause mild shock and 40s will kill your plants with repeated exposure. Keep your plants warm, especially the roots. Elevate pots if you think the ground is sucking the heat out of the roots. This is an issue if you have a slab or other type of cold floor.
As temperature goes up, so does the ability of the air to hold water, thus reducing humidity, so a higher average temperature should reduce risk of fungus.
Contrary to many reports, high humidity is not good for plants except during germination and rooting. Lower humidity levels help the plant transpire CO2 and reduce risk of molds during flowering.
Studies indicate the potency of buds goes down as the temperature goes up, so it is important to see that the plants do not get too hot during flowering cycles.
* D. Gold: CO2, Temperature and Humidity, 1991 Edited by E. Rosenthal.
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DemonTrich
Well-Known Member
shit, i wish i could get my lights on temps below 79*. running a 6" cool tube with a 6" 440 cfm fan, 6" 250cfm intake and 8" 550 cfm exhaust, plus 2 5" clip type fans for circulation. oh, and im running in a tent in a basement with ambient temps at 65-68* year round. im running another tent for flower, which i think ill be running into heat issues. maby another intake fan might help.
My room temp is 79f because I exhaust back into the room ac is on 73f top of tent 84f canopy 88f and my plants seem to be fine. I have a small setup though 250hps dimmed to 75% running dwc and no root issues with those high temps passive intake for neg pressure I guess is the key oh you have to have good air circulations.
Justforme11
Member
How are you keeping it that cool? I have read enough of your threads... I know you grow in soil and have a bigger room than me... I have a cabinet and had too much lighting, but I reduced it a lot (based on some things you wrote, and my own experimentation.) I can't get below 84f no matter what I try. I was hoping to get down into the 70's and I have higher hopes for my flower stage (my red 400 hps is much smaller than my blue... Much smaller, the heat is not as bad with it, I can get down to 80f. Temp is kickin my ass and you are in the 70's? Wow! Am I going to be okay?
