S
sparkjumper
google fluke mini 62 and take reading at canopy tops
Correct way to measure temp under lights?
- Thread starter DevilWeed
- Start date
xcrispi
Member
Damn close to what I was taught as well , 78 degree leaf surface temps for max photosynthesis .
Crispi
W
whiterasta
I use 6' light rails so my lights are in motion over the canopy so besides having a strong airflow past the bulb in my vented parabolics I record temps from -light directly overhead/light at furthest travel at the canopy top and avg. With 1.4k vented parabolics and a small freestanding A/C I keep 14x12 @ 72-79 burning 2.8k 18hrs for veg. For flower the canopy stays 68-74 measured the same way. accounting for HPS high infrared radiant heat is the big problem in measuring a room in only a couple places. Even a small grow like mine(8x8) one should really have a measurement for each 2ft2 as hot spots can easily develop and not really show damage until well into the flower cycle.
So to be fully accurate I do canopy, floor and ceiling every 2ft2 and in doing so found a hot corner running 10 degrees warmer than the rest of the floor. Rearrangement of the circulating fans solved this but I would never have known save in poor yield about the problem without a complete temp profile of the entire room.
WR
So to be fully accurate I do canopy, floor and ceiling every 2ft2 and in doing so found a hot corner running 10 degrees warmer than the rest of the floor. Rearrangement of the circulating fans solved this but I would never have known save in poor yield about the problem without a complete temp profile of the entire room.
WR
Agreed.
This is where i position my thermometers. All 3 books I read when I was learning said to do so. 70-75 degrees at canopy works fine for me.
When I used that style of thermometer, I used to just [partially] wrap the probe in foil tape and draped it over the canopy. You get air temp without the probe heating up under the lights.
For years ive used temp controled speed controls to run my inlet and outlet fans .
i set the desired temp 23c and i always clipped the sensor about a foot from top of a plant under a leaf in medium airflow.
this was the position were the plants took up most nutrients ect .
i set the desired temp 23c and i always clipped the sensor about a foot from top of a plant under a leaf in medium airflow.
this was the position were the plants took up most nutrients ect .
I have temp gauges all over my room, so i can see what the temp is in many different areas.
The main one I judge where to set the ac at by is one that hangs from the ceiling in the center of the room, just above the level of the lights, I figure heat rises so this should give me an idea of the true room temp.
IMO if the light is shining directly on the gauge you will get an artificially higher reading then normal.
The main one I judge where to set the ac at by is one that hangs from the ceiling in the center of the room, just above the level of the lights, I figure heat rises so this should give me an idea of the true room temp.
IMO if the light is shining directly on the gauge you will get an artificially higher reading then normal.
abnormalgrowers
Member
I personally think that a man with two clocks never really knows what time is it. I think that non-professional sensors are meant to give you an approximate idea of what's going on and let you know if you have to get in alert. If you want to have a real cheap reading, use a mercury therm.
Probably best way is to use a laser therm gun, but don't know if works with plants..probably you could put a dummy object at that height and measure his therm..
Anyways we're full of digital cheap therms everywhere so we also taped one at 14" hanging from the 250W HPS so that we can monitor the canopy height and the "temperature"...
Probably best way is to use a laser therm gun, but don't know if works with plants..probably you could put a dummy object at that height and measure his therm..
Anyways we're full of digital cheap therms everywhere so we also taped one at 14" hanging from the 250W HPS so that we can monitor the canopy height and the "temperature"...
reckon
Member
I use a laser thermometer all the time,....I got the one that reads from -4F to +950F so I can also use it for cooking (frying, broiling, bbq, smoker temps), growing, and working on bikes/cars
I got this one from hong kong phooey,..err,..harbor frieght:
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96451
it's surprisingly accurate for a $30 therm,..I took it to a buddies welding shop, and it checked out within +/- 3 degrees.
I found out I had a 90+ degree hot spot way back in the corner of my grow, so I added a fan there, and now it's back in the 70's.
best money I spent on the garden since PH test strips.
I got this one from hong kong phooey,..err,..harbor frieght:
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96451
it's surprisingly accurate for a $30 therm,..I took it to a buddies welding shop, and it checked out within +/- 3 degrees.
I found out I had a 90+ degree hot spot way back in the corner of my grow, so I added a fan there, and now it's back in the 70's.
best money I spent on the garden since PH test strips.
abnormalgrowers
Member
This is a great news for me! So my next therm will be an IR therm, and I can finally get a single true measure.
Anyways on DX you can find it for better prices!
