Where to put your thermometer?!?

So i have a combined thermometer and barometer (moisture).
But where should i place it?

I get wildly diffrent reddings depending on where i put the cord thingy.
The moisture level is consistant though.

Here is a picture to illustrate my problem:


larger image: http://i.imgur.com/Hne0hbY.jpg

And here's the readings:
1. 26*C (78.8*F) just outside the main light area
2. 29*C (84.2*F) in the middle of light area aproximatly 30 cm (12") from 250 W MH
3. 25*C (77.0*F) in shade from basilica
4. 24*C (75.2*F) represent putting the thermostat somewhere else in the room.

So where should i put it?
And how much do you recommend for a northen light autoflower?

Cheers!

I hang mine from my xxxl cool tube hood. its about 4" above the tops of the plants.

i've always heard the rectum to get the most accurate results..

(sorry, i had to as it was much too easy)..

but seriously, you want it around the canopy height as that's where the temperature is the most important obviously imvho..

+1 in the butt

racerboy71 said:

i've always heard the rectum to get the most accurate results..

(sorry, i had to as it was much too easy)..

but seriously, you want it around the canopy height as that's where the temperature is the most important obviously imvho..

Click to expand...

+1 for the rectum

+1 for the canopy. I wondered about this too. Googled it and the answer is obvious..all you want to know is how hot the plants are.

Sorry I couldn't help my self either, I set mine on the side of the pot when small. I don't have a probe on my unit, but I attached it to a stick so it sits at canopy level.

Top of canopy.

Allredy tried but, but it was to hot for the seedlings

ok so top of canopy. thx guys.

can anyone answer my other post https://www.rollitup.org/newbie-central/745610-nutrition-help.html

Yep top of canopy is a good spot for sure.

multiple, they're cheap

BarnBuster said:

multiple, they're cheap

Click to expand...

+1

Can't believe I haven't thought of that...

Ya there really cheep,I use temp/humidity gauges.

for a small room I use 5,larger area I use more.
one close to the ground,one waist height,one above canopy(roof),one directly at canopy,and one by the equipment

NightOwlBono said:

Ya there really cheep,I use temp/humidity gauges.

for a small room I use 5,larger area I use more.
one close to the ground,one waist height,one above canopy(roof),one directly at canopy,and one by the equipment

Click to expand...

...exactly, I get this type for about $3 at Menard's. Not the most accurate, but close enough

I put one on a wall about the same level as the plants, and one amongst the plants. The one among the plants I try to keep out of the direct light, as that can give you a temp that is higher than the ambient air temperature due to radiant heat being absorbed by the thermometer.

And don't lay it on the soil of your pot or you will get a false high humidity reading after watering when the soil surface is wet. And after watering the excess dampness can fry the thermometer. In my case, I was able to fry two thermometers that way until I realized what was going on.

so whats the point having many if the only one that matters are the one over the canopy?