Temperature Ranges of Cannabis

Hey,

Outdoor/Indoor Grower here. My set up is in my house with no air conditioning, and the thermostat i leave next to it gives me the maximum and minimum temperatures for the day/week/whatever. When the suns is directly on the unit it has read up to 140 degrees (ouch!) and i saw it at 132 a few days later. There is adequate air flow, and it usually remains around 90 in the daytime (78 at night)... Is direct sunlight this extreme ok for my little ones??

tl;dr

What temperatures do Cannabis Plants thrive at?

Oh shit no. Thats far too hot bro, 70-80 tops, you will harvest very little unless you cool the joint or dont grow indoor during summer. Fuck thats hot 140.

The sun shining directly on it will give a false reading. Put it in the shade to get a true one.

Daytime conditions should be 70-80 degrees without co2, 80-90 degrees with co2 until the last two weeks when daytime temps should be kept between 70-80 and co2 can be reduced to adjust for the lower metabolism. Night temperatures should be kept above 60 degrees to prevent stress. It is preferrable during flowering to have a night temperature drop of 10-20 degrees to stimulate flowering hormones and reduce stem elongation.

babysas said:

Daytime conditions should be 70-80 degrees without co2, 80-90 degrees with co2 until the last two weeks when daytime temps should be kept between 70-80 and co2 can be reduced to adjust for the lower metabolism. Night temperatures should be kept above 60 degrees to prevent stress. It is preferrable during flowering to have a night temperature drop of 10-20 degrees to stimulate flowering hormones and reduce stem elongation.

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Not trying to be a ball buster but where did you get this info? I think it's incorrect. I have read the ten to twenty degree drop myself, I think it's wrong. To the best of my knowledge current wisdom says to try to keep your environment as close to the same with lights on or off. Those big temp swings will help promote stretching not keep it to a minimum. I try to keep my temps within five degrees lights on or off. Lastly, some strains are going to stretch like crazy regardless, unless you hit them with bushmaster.

well it never really cools off here... we just get a rainy season for about 4 months they are only catching direct sunlight during the early morning, late afternoon, so i dont think they are catching the extremes. but it is usually around 90 degrees in my house unless theres a nice breeze. they seem to be doing ok, i figured the actual sunlight they are getting would be beneficial.. but then again this is my first grow

If you do not believe that weed likes 70-80 F then go ahead and learn your lesson the hard way. High growing temperatures will definitely ruin the crop; low temps make it grow agonizingly slow (if they do not kill it).

In my experience, it is the average temperature of the grow room (not the daily high) that makes a BIG difference.

I am pretty sure that, one year, an average temperature over 100 degrees caused a whole crop of Cheese to turn hermaphrodite (not one single female out of ten but - and this ain't no bullshit - I smoked the male flowers and they were perfectly stony).

I have a big bunch of sprouts going this year. It is too cold outdoors now, but by March I plan to put them in the garage and use 1250 watts of lighting to heat up the room to 80-90. I have lots of co2 also. Without co2, I definitely would not attempt to grow in a room with ave temps over 90. This year I am going to try putting an ice chest in the grow room (it is 8'x8'x7') with a fan blowing on the ice for 12 hours. I did the math and I am hoping that this method will cool things down 5 degrees or so.

I lived in Kampala for a couple years when I was a kid. It is just about 75 F year 'round there. Marijuana plants grew into trees that were 20 feet tall and as big around as your leg.