Flowering temps higher under LED?
- Thread starter Bookush34
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friedguy
Well-Known Member
Most LEDs normally don't put out much IR (unless they are designed to do so). IR heats the leaves beyond ambient air temperatures. It's the temperature of the leaves that regulate transpiration, not the air temperature.
To get the leaf temperature of plants growing under LED closer to plants growing under MH/HPS/CMH you need to raise the ambient temps (or add IR).
To get the leaf temperature of plants growing under LED closer to plants growing under MH/HPS/CMH you need to raise the ambient temps (or add IR).
That’s what I have read as well.
Would you say 80-85 is accurate?
Renfro
Well-Known Member
Yes, if not using CO2 enrichment.
Humanrob
Well-Known Member
So what would be the expected negative impact/result of running LEDs in a grow that spends much of it's time in the 70-74º range?
I have personally found my plants grow slower below 75f with my LEDs.
Can’t compare to MH/hps as I could not get my temps that low. Hence the LED swap
jarvild
Well-Known Member
Not much to me. My flower room never runs over 77 degrees.
The right has 5 IR chips with supplemental reds and the left is just Sammy strips with no supplements. The right is 2 week behind on flowering time.
Again a max temp of 77 degrees
Humanrob
Well-Known Member
Thanks for the replies. I'm growing in a difficult to regulate garage, and with the current outside weather this has been the coolest I've ever run a grow. I'm OK if they take a little longer, I'm hoping I won't lose too much mass or density. So far so good. I have a 3x3 and a 2x4, the pic is the 3x3 at about 4 weeks into flower.
There are four plants in there (each different strains), 5 gallon pots of soil, 5 weeks of veg, just under 40w/sf of cobs.
There are four plants in there (each different strains), 5 gallon pots of soil, 5 weeks of veg, just under 40w/sf of cobs.
Humanrob
Well-Known Member
Beautiful looking plants. After a handful of years of growing it appears that there are a lot of ways to do this, and it's a system so no factor (like temps) exist in isolation. Looks like you've found a very nice balance.
Because of the cold and also the wind we're having right now, the heat running stronger is drying the air out, I'm down mostly around 50-55% (low for here). Cool temps and low RH is a new combo for me, but the plants are doing OK so I'm going to run it out and see how it goes.
SPLFreak808
Well-Known Member
One thing that seriously caught my eye was growth speed during the first 4-6 weeks.
temperature seems to play a role with my yield if i let it get too cold too soon. Anything after 4-6 weeks doesn't seem to have as much of an effect as long as its not too cold, this would likely depend on your light output,wavelength & temperature of the root zone.
Lately i have been having decent results running the schedule below and am seriously thinking of sticking to it.
80-82f (weeks 1-4) 78-80f (weeks 5-6) , 75-77 (weeks 7- 8
temperature seems to play a role with my yield if i let it get too cold too soon. Anything after 4-6 weeks doesn't seem to have as much of an effect as long as its not too cold, this would likely depend on your light output,wavelength & temperature of the root zone.
Lately i have been having decent results running the schedule below and am seriously thinking of sticking to it.
80-82f (weeks 1-4) 78-80f (weeks 5-6) , 75-77 (weeks 7- 8
Humanrob
Well-Known Member
To have that kind of control I'd have to run the heat all night and morning, and the AC all afternoon and evening... I'm just not running the electric that high, by the time I was done I could probably buy the pound for what the bill would come to (Oregon is pretty saturated these days). But I do envy and respect anyone who can keep things that tight.
SPLFreak808
Well-Known Member
Haha mybad, should have mentioned thats with the lights on. I don't mind a temp swing during dark hours as long as its not too wide to cause excessive stretch.To have that kind of control I'd have to run the heat all night and morning, and the AC all afternoon and evening... I'm just not running the electric that high, by the time I was done I could probably buy the pound for what the bill would come to (Oregon is pretty saturated these days). But I do envy and respect anyone who can keep things that tight.
For me, its fn hot & humid 24/7 and works nicely with just an a/c & dehu, alot easier to control compared to any HID i have tried, i do grow in a sealed room so i hate to see it swing when im already paying for stability.
Electricity,heat & rh is ridiculous out here so i don't really have a choice but to use the a/c during light hours and a dehu 24/7, its how the game goes.
Brock_Fawkin_Samson
Active Member
Are these air temps or LST's?
Rocket Soul
Well-Known Member
Slower transpiration (depending on RH aswell) and a slower metabolism. Slower transpiration can lead to the plant not uptaking enough nutes, especially C and Mg, which can make the plant prone to deficiencies and light shy, prone to bleach. And growing slower.
I think most of them are air temps but with led airtemp and leaf surface temps are very similar.
Rocket Soul
Well-Known Member
Im hoping to get my hands on some IR strips asap. Has anyone tried running IR during the dark cycle to heat anda boost plant metabolism? I love how bulky those ir buds look.
jarvild
Well-Known Member
That would be my choice. I'd rather run 20 watts of IR than run 600-1200 watts of heating to get my temps up.
blazeottawa
Member
I have heard the terpines can be damaged at those temperatures. Also it makes the plants vulnerable to some plagues like Spidermites.