Fum "new Greenhoues"
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StoneyBud
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Ideal temps are 75F for the root system and 75-85F for the above ground parts of the plant.FUM said:How "HOT" is to hot/// Inside the greenhouse. I just looked and we're right at 102. Plants lookin'great.
At 90F, the plants will start slowing their growth with most strains. At 100F, many strains just stop growing or grow very slow compared to what they would grow at 75F.
102F is pushing the limit. Your plants will be much happier with lower temps.
ozzydiodude
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:yeahthat:IMO the hotter the grow area the more likely you will have a bug problem. It seems that bugs show up every time the intake or exhaust fans go down.
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420grower
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as a greenhouse grower,I have noticed if you keep your plants in the center of the house and keep them tied under 3 ft tall you can with exhaust and fans moving air temps can be kept in check,I use a 60%shade cloth from june thru sept.makes a huge difference,and not to start trouble but high temps don't slow growth at all in fact they become quite leggie and thin,root temps over 90 yes,will cause growth slowing,but that is rare in house due to plant shading,water cooling ect.hey The Dr. has spoken,haha,good luck,order a shade cloth life will become much simplier,also a good misting system on a temp sensor works great lowering temps and is a cheap add
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StoneyBud
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420grower, you're right of course. I was mistaking root temps for room temps...Good catch.
Here's some information on it from Ed:
TEMPERATURE
D. Gold: CO2, Temperature and Humidity, 1991
Edited by E. Rosenthal.
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, marijuana 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 marijuana 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 50’s will cause mild shock and 40’s 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.
Here's some information on it from Ed:
TEMPERATURE
D. Gold: CO2, Temperature and Humidity, 1991
Edited by E. Rosenthal.
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, marijuana 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 marijuana 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 50’s will cause mild shock and 40’s 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.
leafminer
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Yeah, Stoneybud's right, I have been getting temps of 38-40C every day for months, and there is no doubt my plants are not putting on bud as they should. I would rig up a mister to drop the temp in that area of the garden but then I'd be concerned about mould. I see a big difference in the quality of my bud once the temp gets much over 30C. Tends to become 'airy'. You know what I mean.
I'm confused. I put my plants in on the first of July they were 3 or 4 in. Today they are 2ft tall. I know that I don't want BUGS,I want BUDS. So for the time being going to run the greenhouse at 75 to 85 sound safe and sane.Thanks for all the tips fellow growers. We rule!!!
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