Proper method of taking temperature in grow cabinet?

F

funlovingfool

Member
Hi everyone. Hope you are all well. The temps in my cabinet have been borderline too high. I use an electronic thermometer that has the little probe on the end of a long wire. I had been putting it up about halfway to my light to take my temps. But I recently read where someone said to not let the thermometer/probe be exposed directly to the light emitted from the HPS, otherwise you would get a false temp. Seems to make sense. The probe is black and could absorb the heat. Whats the best method for getting an accurate reading of temps? Thanks in advance. :-P
 
budlover13

budlover13

King Tut
i've always heard (and practiced) having my sensor at the top of my plants for an accurate reading of the temps they are subjected to.
 
gnarlycallus

gnarlycallus

New Member
im pretty sure it gets hotter the closer you go. like with say four cfls measured at six inches, and compare it to a 150hps at a foot, the cfls would appear hotter
 
jondamon

jondamon

Well-Known Member
I have my temp gauges at different places in my grow room

1 at pot level
1 at canopy level but out of direct light so radiant heat doesn't mislead the readings
1 on a side wall

This way I get multiple readings of my growing area.




J
 
darkdestruction420

darkdestruction420

Well-Known Member
budlover13 said:
i've always heard (and practiced) having my sensor at the top of my plants for an accurate reading of the temps they are subjected to.
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Agreed. As for it being exposed to the light-you seem to have a different model than i do. i have one's(i have 4 throughout the grow area so i have a good idea of what the temps are like all over the canopy as i have cfl sidelighting i try to keep as close as possible) that are white and have a metal piece at the end. I know mine work just fine exposed to the hps light.
 
F

funlovingfool

Member
Thank you for the advice people. My cabinet is small with a (28Lx14Dx47H) flowering chamber. I am currently doing "dry runs" to iron out temperature issues before I risk planting some beans. Getting high temps of 88.5 using a 6 inch booster fan venting through the top of the cab, and a passive intake on the back near the bottom. Which isn't so good considering ambient temps are around the mid 60's. My light is a 250w HTG HPS. I'm trying to avoid making a glass partition between the light so I won't lose lumens and can adjust the reflector accordingly. I purchased 3 more 120mm computer fans that I am hoping to strategically place to cool the cab down some. Perhaps one blowing across the lamp, and the other two blowing across the canopy on each side. Or perhaps one mounted to the exhaust vent to help "boost" the booster fan. Eventually when I can afford it though, I would like to invest in a 4 inch inline fan if necessary. But for now I'm trying to figure out a way to get this to work the best with what I have till I can upgrade.
 
B

Bush Therapy

Active Member
FunLovingFool,

I fear you're fighting a losing battle. I use a grow cabinet and I too fought high temps until I gave in and bought a cool tube for my light, through which I draw and exhaust outside air, using ducting, with a 400+ cfm fan. That made the high temps more manageable. I also ventilate the cabinet through several layers of charcoal impregnated pads, using a 4" 80+ cfm fan, set on both a timer (for regular air exchange) and a line-voltage thermostat (for cooling). The system seems to work well unless it's the height of the summer. I don't grow then.

Best of luck to you.
 
budlover13

budlover13

King Tut
darkdestruction420 said:
88.5 isnt that bad. i hit low 90's at times and its alright.
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During winter, spring and fall my max temps are in the high 70's. During summer i occasionally hit mid to high 80's when vegging and the lights are on for longer periods thus necessitating them to run during the day. Flowering i run them 7pm-7am. i also grow in a full-size 10X11' bedroom rather than a tent though.
 
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