Temperature HELP PLEASE +rep 4 solution

B

BeatenByTheWorld

Well-Known Member
My buddy has a small area set up and cannot stabilize the temp. The ambiant room temp. is at a steady 82, HOWEVER the 'canopy' temp is almost at 90, with the lights at 24 inches away.

It is our understanding that 75-80 degrees is ideal but nobody ever says whether thats room temp or canopy temp.

He is running air cooled lights on a 424 CFM fan. Air is coming from outside the room (60-70degrees) and is being pulled across the lights and being exhausted back out of the room. He is also running a box fan blowing at the canopy.

Can anyone tell us what the problem is and if there is one?
Is the thermometer inaccurate because its directly under the light?
Is it suppose to be that temp at the canopy?
 
Little Tommy

Little Tommy

Well-Known Member
Yes, you are looking for the temp that the foliage is experiencing. Depending on where you place the thermometer makes a difference. I find that careful fan placement also makes a difference. I have my fan pointed so that it sweeps back and forth across the plants and the bottom of the light. What size light are you using?
 
R

ROBINBANKS

New Member
Maybe of some help dude...

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
 
I

Illegal Smile

Guest
The key there is the 82 degree room temp, too warm. If you want canopy temps to stay in the high 70s you need to get the room temp to low 70s. In other words more AC. Fans may help a degree or so but 90 is too warm. Heat is a bitch and AC is the only real weapon.
 
G

growone

Well-Known Member
You mention that thermometer is close enough to the light that you're concerned whether you are getting a good temperature. If that's the case, you probably have cause. Temp measuring is very important.
One cheap trick is to put some kind of 'shield' between the light and the thermometer, that will improve your confidence that the temp is the ambient temperature. I had a temperature probe hanging up close to my lights. Used a bit of aluminum foil as a 'shroud', that dropped the temp reading by 5 degrees(Fahrenheit). That was the difference between a big change in my setup and going with what I had.
 
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