NoLimit916
Active Member
Hello growers! I used to grow in Hps and I’m now switching to LED’s. I know that the temperature in an HPS during flower is about 75 degrees F. Now that I’m switching to LED, what is the ideal temperature in flower? Thanks!
Proper temperatures in LED grow
- Thread starter NoLimit916
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What led are you using?
NoLimit916
Active Member
I’m using 4 HLG-600.
Rocket Soul
Well-Known Member
Low 80ies generally, 81-84F.
projectinfo
Well-Known Member
I like my room around 22c
It keeps my res water at 19c
It keeps my res water at 19c
NoLimit916
Active Member
The temperatures that you gave, is that in veg or in flower?
Rocket Soul
Well-Known Member
The vpd calculator is quite handy:
http://opennlabs.com/vpd/VPD_calculator.php
It allows you to calculate proper temp and RH, this one also allows you to adjust to leaf temprature (being lower for leds than HPS). Id use -1 for your lighting and +2-3 for hps. Remember that its more a guideline than a bible, something to use to dial in which direction to take your enviroment rather than absolutes.
http://opennlabs.com/vpd/VPD_calculator.php
It allows you to calculate proper temp and RH, this one also allows you to adjust to leaf temprature (being lower for leds than HPS). Id use -1 for your lighting and +2-3 for hps. Remember that its more a guideline than a bible, something to use to dial in which direction to take your enviroment rather than absolutes.
NoLimit916
Active Member
Thank you! Is that all the way thru flower?
Rocket Soul
Well-Known Member
Maybe a bit cold for leds. Ive seen 28-30°C been recommended.
projectinfo
Well-Known Member
Veg
projectinfo
Well-Known Member
Im perfectly in the blue for early veg cloning
diyled
Well-Known Member
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4598144/
"
Conclusions
The presented model indicates that the use of LED technology reduces leaf temperature by about 1.3°C compared to HPS technology under typical, indoor growing conditions. While this is a significant difference for some applications, the difference is smaller than the difference between indoor and outdoor leaves. Because of differences in net longwave radiation, a leaf in a controlled environment will be warmer than a leaf in the field under a clear sky, assuming equal PPF and similar environmental conditions. In conditions where leaves benefit from heating, such as a greenhouse in a cool climate, HPS technology more effectively transfers heat to canopies."
"
Conclusions
The presented model indicates that the use of LED technology reduces leaf temperature by about 1.3°C compared to HPS technology under typical, indoor growing conditions. While this is a significant difference for some applications, the difference is smaller than the difference between indoor and outdoor leaves. Because of differences in net longwave radiation, a leaf in a controlled environment will be warmer than a leaf in the field under a clear sky, assuming equal PPF and similar environmental conditions. In conditions where leaves benefit from heating, such as a greenhouse in a cool climate, HPS technology more effectively transfers heat to canopies."
What would be the upper limit for LST?
The wireless temp/humidity sensor hangs touching one of the walls at canopy height, actually an inch above. Temps for the past couple of days as per the sensor have been touching 30-32°C. Highest LST measured has always been 3-5° lower than what the sensor displays. I think the sensor's plastic housing is skewing the temp.
Daytime humidity at canopy level is 55-60, below the canopy (inch above coco) daytime goes up to 75-80. Are these temps and humidity levels alright or do I need to make adjustments?
Night temps are 24-26°C. Humidity sits at 60 at canopy level and 65 at pot level (inch above the coco), sensor lies flat on the pot's rim/edge.
Lights being used - 3000K 80 CRI QBs. 2 560 boards are pulling 125W each. Hanging distance is 18 inches.
Lux is currently at 35000-40000, which I'd like to increase (2ndweekflower). Can I lower the lights further or should I raise them to 24 inches and crank them to 175-200W?
As you can see I'm a little lost/confused. Please help.
Thanks
The wireless temp/humidity sensor hangs touching one of the walls at canopy height, actually an inch above. Temps for the past couple of days as per the sensor have been touching 30-32°C. Highest LST measured has always been 3-5° lower than what the sensor displays. I think the sensor's plastic housing is skewing the temp.
Daytime humidity at canopy level is 55-60, below the canopy (inch above coco) daytime goes up to 75-80. Are these temps and humidity levels alright or do I need to make adjustments?
Night temps are 24-26°C. Humidity sits at 60 at canopy level and 65 at pot level (inch above the coco), sensor lies flat on the pot's rim/edge.
Lights being used - 3000K 80 CRI QBs. 2 560 boards are pulling 125W each. Hanging distance is 18 inches.
Lux is currently at 35000-40000, which I'd like to increase (2ndweekflower). Can I lower the lights further or should I raise them to 24 inches and crank them to 175-200W?
As you can see I'm a little lost/confused. Please help.
Thanks
If I lower the temp/humidity sensor from an inch above the canopy to an inch below, humidity shows a rise from 55-60 to 70-75 (lights on). Which humidity value is valid for our purpose? Also what's the better location, an inch above or an inch below? Somewhere in between the canopy and coco?
Night time is no problem, 26°C and 56%. Even the sensor near the pot is at 60%.
Night time is no problem, 26°C and 56%. Even the sensor near the pot is at 60%.
Rocket Soul
Well-Known Member
I think youre quite fine for now. But i would definitely try to get some air movement under the cannopy cause 80RH is a lot, both for vpd and PM. Look into lollipopping your flowers for the next time.
I have 2 small USB fans sitting between the pots blowing upwards. Another 3 bigger ones at different heights blowing above and at the canopy. Everything flutters/rustles, even the tiny leaves in the centre that hardly get any light.
Lollipoped a bit below the first topping before flipping, plan on removing everything below the 2nd topping that hasn't made it to the top once 3 weeks are up.
Dehumidifier should be here by Monday.
Rocket Soul
Well-Known Member
Did you like the new lights? Do you feel you get an even spread out of them? How was r2t like to deal with, was it Russel?
Yes.
For a 4.5 x 1.7 the spread is quite uniform. Lux drops a bit towards the sides as the boards sit a little inside the heatsinks. Deal went smooth. Not a man of many words but to the point and from what I can tell, he's honest. Was clear that for such small orders they make the boards by hand and not a pick & place machine. They forgot to ship the hangers but did so the very next day once informed. All in all it was satisfactory.
Shaded the canopy level sensor using a piece of cardboard with aluminium tape on the top side.
Temp has dropped from 32 to 28.5, humidity 64%. The difference in LST for QB's also makes a lot more sense now, actual difference is 1-2°. Been looking at charts with a difference of 3-5° till now.
1 - canopy, 2 - First topping 'Y', 3 - ground level
