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Thread: Question about temperature (1st grow)

  1. #1
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    Exclamation Question about temperature (1st grow)

    Hi, I have a 4x4x7 tent running a 600w digital ballast; carbon filter, and 6" fan.

    I'm currently running 12/12 for flowering. During the day (when light is on 12 off cycle) the temperature inside the tent is 78-80 degrees.

    When the light is on the temperature shoots up to 90 degrees.
    Is this too hot?
    I was told to keep temp between 75-80 degrees.

    Thanks in advance for input.

    -havik

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    News Moderator The General's Avatar
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    Re: Question about temperature (1st grow)

    Yes, that is too hot! Anything over 80 and plant growth slows or stops.

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    420 Member Fuzzy Duck's Avatar
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    Re: Question about temperature (1st grow)

    Some ideas to reduce temperatures...

    1. Air cooled reflector & secondary fan.

    2. Open up a passive vent at base of grow tent so that the extractor fan is pulling new air through the tent as it vent the hot air.

    3. If not all ready done ? Lights on period at night time as ambient tempes will be lower than the day time.
    We are a culture fully immersed in the ideology that truth is what we see and what we hear. Yet we hire lawyers to manipulate truth, we hire PR and marketing firms to create truth, and we hire investigators and private detectives to uncover truth. The problem to which I am affected every day is truth in the cannabis industry.

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    420 Member beemerbill's Avatar
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    Re: Question about temperature (1st grow)

    Heat is not good and I have struggled with high temps my whole grow. When we were still in vegging I came home from work and looked at the temp in the tent and it was at 96 degrees. YIKES what am I going to do. I added another exhaust fan into another carbon filter but still no help. I finally broke down and bought a 7500 btu free standing A/C unit. I vent the heat outside and I can keep the temps down to right at 80. My main problem is the garage gets to warm. My 1000 watt light is a cool hood that I run 6" ducting out of the tent and up into the attic. This is my first grow and the next one WILL be lights on at night probably starting around 9 as the day is getting cooler then. Good luck with trying to keep the temp down.

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    420 Member 209 Cali C.G's Avatar
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    Re: Question about temperature (1st grow)

    Quote Originally Posted by Elhavik View Post
    Hi, I have a 4x4x7 tent running a 600w digital ballast; carbon filter, and 6" fan.

    I'm currently running 12/12 for flowering. During the day (when light is on 12 off cycle) the temperature inside the tent is 78-80 degrees.

    When the light is on the temperature shoots up to 90 degrees.
    Is this too hot?
    I was told to keep temp between 75-80 degrees.

    Thanks in advance for input.

    -havik
    75f to 80 is good, but I find 80f to 90f works just fine too.To me 85f is the sweet spot for my room.Plants use more water, and plants seem to love the heat too.

    I live in Cen Valley Cali, and the outside temps are 100+ and plants are fuck growing fast outdoors!

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    420 Member 209 Cali C.G's Avatar
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    Re: Question about temperature (1st grow)

    Quote Originally Posted by The General View Post
    Yes, that is too hot! Anything over 80 and plant growth slows or stops.
    That is just not true.Most of the time it's more then that, that makes there plant grow slow.

    My friend grows in his garage, and I saw his temps hit 98 with a 1000w, but plants are doing good, but will add that high temps are not good if you got a bug problem!They love heat.

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    News Moderator The General's Avatar
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    Re: Question about temperature (1st grow)

    Ed Rosenthal's Grow Tips

    Maintaining Optimum Grow Room Temperature
    Marijuana plants are very hardy and survive over a wide range of temperatures. They can withstand extremely hot weather - up to 120 degrees - as long as they have adequate supplies of water. Cannabis seedlings regularly survive light frost at the beginning of the season.

    Both excessively high and low temperatures can slow marijuana's rate of metabolism and growth. The plants function best in moderate temperatures - between 60 and 85 degrees. As more light is made available, the ideal temperature for normal plant growth increases. In high temperature and moderate light conditions, the plant's stems elongate. Strong light and low temperature conditions will decrease stem elongation. During periods of low light, sem elongation can be decreased by lowering the temperature.

    Temperatures below 50 degrees slow growth in most varieties of marijuana. When the temperature drops below 40 degrees, the plants may experience some damage and require about 24 hours to resume growth. Low nighttime temperatures may delay or prevent bud maturation. Some equatorial varieties stop growth after a few 40 degree nights.

    A sunny room or one illuminated by high wattage lamps heats up rapidly. During the winter, the heat produced may keep the room comfortable. However, the room may get too warm during the summer. Heat rises, so that room temperature is best measured at the plants' height. A room with a 10 foot ceiling may feel uncomfortably warm at head level but be fine for plants 2 feet tall.

    If the room has a vent or window, an exhaust fan can be used to cool it. Totally enclosed spaces can be cooled using a water conditioner which cools the air by evaporating water. If the room is lit entirely by lamps, the day/night cycle can be reversed so that heat is generated at night, when it is cooler out.

    Marijuana is low-temperature tolerant. Outdoors, seedlings sometimes pierce snow cover, and older plants can withstand short, light frosts. Statistically, more males develop in cold temperatures. Low temperatures, however, slow down the rate of plant metabolism. Cold floors can lower the temperature in containers, thereby lowering root temperature and slowing germination and plant growth. Ideally, the medium temperature should be 70 degrees.
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    420 Member 209 Cali C.G's Avatar
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    Re: Question about temperature (1st grow)

    Quote Originally Posted by The General View Post
    Ed Rosenthal's Grow Tips

    Maintaining Optimum Grow Room Temperature
    Marijuana plants are very hardy and survive over a wide range of temperatures. They can withstand extremely hot weather - up to 120 degrees - as long as they have adequate supplies of water. Cannabis seedlings regularly survive light frost at the beginning of the season.

    Both excessively high and low temperatures can slow marijuana's rate of metabolism and growth. The plants function best in moderate temperatures - between 60 and 85 degrees. As more light is made available, the ideal temperature for normal plant growth increases. In high temperature and moderate light conditions, the plant's stems elongate. Strong light and low temperature conditions will decrease stem elongation. During periods of low light, sem elongation can be decreased by lowering the temperature.

    Temperatures below 50 degrees slow growth in most varieties of marijuana. When the temperature drops below 40 degrees, the plants may experience some damage and require about 24 hours to resume growth. Low nighttime temperatures may delay or prevent bud maturation. Some equatorial varieties stop growth after a few 40 degree nights.

    A sunny room or one illuminated by high wattage lamps heats up rapidly. During the winter, the heat produced may keep the room comfortable. However, the room may get too warm during the summer. Heat rises, so that room temperature is best measured at the plants' height. A room with a 10 foot ceiling may feel uncomfortably warm at head level but be fine for plants 2 feet tall.

    If the room has a vent or window, an exhaust fan can be used to cool it. Totally enclosed spaces can be cooled using a water conditioner which cools the air by evaporating water. If the room is lit entirely by lamps, the day/night cycle can be reversed so that heat is generated at night, when it is cooler out.

    Marijuana is low-temperature tolerant. Outdoors, seedlings sometimes pierce snow cover, and older plants can withstand short, light frosts. Statistically, more males develop in cold temperatures. Low temperatures, however, slow down the rate of plant metabolism. Cold floors can lower the temperature in containers, thereby lowering root temperature and slowing germination and plant growth. Ideally, the medium temperature should be 70 degrees.
    that info is way out dated, even ed said that.

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    Re: Question about temperature (1st grow)

    at the most it gets to about 91 degrees after the 600w lights been on for 10 hrs. i did notice that 1 of the 5 plants is not really growing. i've only had them in there for 1 week. so today, i changed the order of the plants, and put this one closer to the light.
    the plant on the left (closest to the camera) is the small one, i switched with the one in the middle.
    these were taken 3 days ago.


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    Re: Question about temperature (1st grow)

    it can also help to add some co2 enrichment during the lights on time,it speeds growth and helps with heat tolerance, Jorge cervantez says the point where growth slows is 85f ,i think it can depend on strain too.

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    Re: Question about temperature (1st grow)

    Hey All-

    Figured I'd resurrect an old thread rather than start a new one. I'm on my first grow as well. The first question is when you all are taking temp readings are you testing down right next to the plant {directly under the lights} or just in the area.

    For example, like the OP, I'm using a 4x4x7 tent and have my thermometer probe pinned down about 0.5" off the soil about 2 inches from the plant.

    The second issue is the garage is 75-85 and might get up the low 90s. I've got the lights running 18/6 with the 6 hours of dark from 11am-5pm. I have a 4" inline fan sucking the hot air from the top and exhausting it through a Carbon Canister Type Filter. I had a couple small fans blowing in there but the draw on the circuit was too much (for now) so I nixed em.

    I'm keeping the girls moist (watering with a little run off each time) about every 3-4 days. The soil is staying damp about 1 knuckle deep, but getting pretty dry up top.

    Thoughts?

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