Where do you measure temperature?

I

IndoorWarrior

Active Member
Just had a thought I figured I'd run by all the experts here.

When do you know the growroom is too hot?

Is it when the ambient room temperature gets above 75-77 , or when the measured temperature directly below the lamps in the growing canopy gets above 75-77?

thanks in advance!
 
you want the ambient temperature to be around 75-85 degrees. The plants can stand a much higher radiant temperature (direct heat from the lamp). I would say put it in the shade near your plants.
 
I measure temperature everywhere in my rooms...
right at the top of the canopy. outside of the canopy. oppsite wall...
i really really want to make sure the temp & rh are straight...best thing you can do for your plants is make them comfortable.
 
thanks for the replies guys. I guess I have another question to clarify then.
so when which thermometer gets over 75-77 do you start to worry?
cause when i hang the thermometer in the growing canopy my temps are consistently above 90, but the plants look good and the last few crops have turned out nice, but its getting warmer here everyday. When I put the thermometer near the ceiling, the measured temperature is about 78.

So is this room in need of more ventilation?
 
i have the same question cause everywhere in my growroom is like 75 or lower except directly under my lights it is hotter, and im using exhaust fan and boxfans in a 8x6x8 growroom
 
i was wandering the same.where do i really place it?under my lamp is something like 90.next to is something like 83-85.is that good?so any experienced growers know where to put that thermometer exactly?
 
i hang mine on a wire between my lights so it hangs right were the tops of the plants are

and i dont let it get over 90 EVER, i prefer 85.

but then again i use an A/C set to 72f to keep the room nice and cool
 
if you only have 1 thermometer i would say the most important place to get a reading is near the plants, since you setup everything to be just right. if the temperature around the plants is within the range of what you want then the other temperatures dont matter as much. (if plant temperature is ok then that prob also means the temperatures around the room are ok as well)
 
measure ur temps at the top of ur plants so have ur theromometers hanging at the same level as the tips of ur plants, u would also want to have fans circultaing the air between the bulb and the tip of ur plants.... 79-82 is said to be the premier temp to grow oin when not using co2
 
when you place your thermometer under the lights - radiant heat - it messes up the results. most thermometers are not made for that. measure in the shade, the plant can take radiant heat temps much higher than 30c/90f
 
I know its a old thread ..

but was acctualy wondering the same .. and trying to find some info .. as some Ppl. do some research themself ;)



I can mostly keep it around 78-80F in the room .. middel hight .. a meter away from the light/plants at the wall ..

if I use my wire and mesure inside my canorpy in the shade it is mostly around 80-84F depending on how high I hang it ..

but if I move it up at the top of my plants .. under the light ... at let it hit it .. I get readings in the end at around 88-92F


so what is right ? if I try to use logical ..I see it like this ...

when you use outdoor temps you allways mesure it in the shade ..
and if temps for a outdoor plant is perfect at 78-80F .. I reccon its a nice summer day ... then it will be a lot hotter in the sun ..
so I guess its in the shade .. of course near the top as its mostlikely is the hottest place ..

but I would try to move it around a bit like I did and see some diffrent readings ..


so I guess asaph is right .. I hope ;)
 
asaph said:
when you place your thermometer under the lights - radiant heat - it messes up the results. most thermometers are not made for that. measure in the shade, the plant can take radiant heat temps much higher than 30c/90f
Click to expand...

This is correct
 
asaph said:
when you place your thermometer under the lights - radiant heat - it messes up the results. most thermometers are not made for that. measure in the shade, the plant can take radiant heat temps much higher than 30c/90f
Click to expand...

Alright I know this is a really old thread, but does this imply that radiant (surface temps) up to 90f are fine and will not cause fluffy buds? I'm really confused because some people say that is correct while others stick to the 74-78F rule even at the plant surface.

I really want to lower my light, but doing so will cause the canopy to get over 78F.
 
I know this is old, but first poster.
I have a 3x3 tent with 5 plants (4 about a month old 1 about 3 weeks but stunted due to spilling it so) so I basically keep a small CFL over it.
I have a 6 inch incline fan with carbon filter attached zip tied at the top of right of the tent. And a small (6in?) but powerful fan (I use high now)it's pulling cool air from a vent at the bottom blowing straight on the plants.
I also have 2 150W HPS I am now using.
I swapped to this about a week ago from a single 150w CFL since seedling. Until I changed to HPS (1 week ago) I had an oscillating fan. I had to go to the smaller fan for space purposes but may end up getting an 8imcn oscillating fan and using the 6inch to pump cool air in from outside .
I topped and cleaned everything below my 3rd node to begin the main lining process when I swapped to hps.
Since they seem to be still growing out fine as I have them held down with pipe cleaner lightly so they grow out to desired length.
The problem is the heat.
I finally got around to getting a thermostate as it was getting hot. And to my surprise it was 90 at the soil, 92 at canopy, and 89-90 at the bottom corner. I guess somewhat in the light. I moved it to the middle. They're in dark now so I will report back tomorrow.
Any recommendations ? I've also got a window unit in the room constantly blowing at 70. And an aircondition house. Is it the size of the tent and the 300W of hps? I swapped to them because of the amount of plants. I'm hoping the 4 will fit if I mainline them properly. I went with mainlining for that purpose. I can grow 4 plants with 8-16 colas as tall as I want since I have a tent is how I figure. I can't fit 3 in this size tent with typical Christmas tree growing. So trying something new. But these lights are new to me and I'm unsure if my fan and inline aren't enough or if I'm measuring in the wrong place ?
Thanks for any help. This is my first post here. Long time lurker. Never ran into a problem I couldnt figure out without asking. Toke on fellow farmers
 
Last edited:
woahthisisfun said:
I know this is old, but first poster.
I have a 3x3 tent with 5 plants (4 about a month old 1 about 3 weeks but stunted due to spilling it so) so I basically keep a small CFL over it.
I have a 6 inch incline fan with carbon filter attached zip tied at the top of right of the tent. And a small (6in?) but powerful fan (I use high now)it's pulling cool air from a vent at the bottom blowing straight on the plants.
I also have 2 150W HPS I am now using.
I swapped to this about a week ago from a single 150w CFL since seedling. Until I changed to HPS (1 week ago) I had an oscillating fan. I had to go to the smaller fan for space purposes but may end up getting an 8imcn oscillating fan and using the 6inch to pump cool air in from outside .
I topped and cleaned everything below my 3rd node to begin the main lining process when I swapped to hps.
Since they seem to be still growing out fine as I have them held down with pipe cleaner lightly so they grow out to desired length.
The problem is the heat.
I finally got around to getting a thermostate as it was getting hot. And to my surprise it was 90 at the soil, 92 at canopy, and 89-90 at the bottom corner. I guess somewhat in the light. I moved it to the middle. They're in dark now so I will report back tomorrow.
Any recommendations ? I've also got a window unit in the room constantly blowing at 70. And an aircondition house. Is it the size of the tent and the 300W of hps? I swapped to them because of the amount of plants. I'm hoping the 4 will fit if I mainline them properly. I went with mainlining for that purpose. I can grow 4 plants with 8-16 colas as tall as I want since I have a tent is how I figure. I can't fit 3 in this size tent with typical Christmas tree growing. So trying something new. But these lights are new to me and I'm unsure if my fan and inline aren't enough or if I'm measuring in the wrong place ?
Thanks for any help. This is my first post here. Long time lurker. Never ran into a problem I couldnt figure out without asking. Toke on fellow farmers
Click to expand...

The even temperature in the tent tells you the air circulation is fine but the high temps mean you're not venting enough of the heat. Can you install an exhaust fan near the top of the tent? That will draw heat out and pull cool air in.
 
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