How hot is too hot

My big question is; What is the optimum temperature for growing / flowering and how hot is too hot? also how cold is too cold?
I have set up a small grow area under a workbench in a 2 car garage w/ no cars in it. It's true growing area is 28" tall x 24" deep x 40" wide. I currently have 500 watts (125 w actual) CFL to light with another 400Watts 2700K waiting for flowering. My big concern is the heat buildup. I have a 4" turbo fan exhausting w/ scrubber and a 8" blade fan intake. my temperature hovers between 65 and 82. I have the lights off from 2:00 PM to 8:00 PM (the hot part of the day) and I freeze a milk jug of water daily and hang it near the plant every morning to keep the temp down. It's just one plant that I intend to flatten out till flowering time and hope for a sea of buds.
This is my second grow but my ol lady vetoed the use of the spare bathtub where I grew last. That room had A/C and heat was not an issue.

Please help. I don't wanna cook my little master kush clone. Not yet anyway.

I would say higher than 86 is too hot

82 is perfectly fine. If you have good ventilation with good fresh air input the plants can do fine at 95-100F. I know from experience (oops). Growth is slower but they still grow.

damn good to know

Thanks PH
any ideas on better ways to keep the temp down. the temp is gonna get hotter here in S Calif as the summer goes on. My Ice jugs came out of desperate fear of cooked Kush and I need a better way to cool while keeping stealth on.

TEMPERATURE - Cannabis Growing Guide

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.

Thanks wyteberrywidow for the input. This is why we all come here. Loads of helpful stoners passing on their knowledge and working together.

Vape on dudes and dudetts

No problem just glad i can help out.