Settle this please. temp needs for LED

What temp would you suggest for a LED setup say like a Mars hydro or a Spiderfarmer? And why?

@harrythehat
@Homegrown Hero


Thanks RIU

I run 78-82F. Nearing end of flower I open the tent and blast it with fans for circulation, and to bring temps down a little (72-75F) at the same time me staring at them. (While smoking one of their dead homies)

Why? From reading up, and skimming thru grow journals on different sites.
I heard most of all that LED gives off less heat than an HPS. So the ambient temps in the grow space need to be warmer to bring up leaf surface temp.

I just started to grow in may.. I picked up a shit ton, but there is still 1000x more info out there.

All info I have read, come across, and been informed here has been mid 80s with 86 degrees / 30 Celsius is the target.

LED lack the IR light to warm the canopy to proper levels. Without the higher temps the plants can't transpire. This is during veg.

During flower I was informed 82 is the target.

I have the SF-2000 for my veg tent and the HLG-550 for my flower tent. I have also vegged under the HLG-550 with great results.

I keep the canopy temps between 78 - 82 degrees F with the lights on. I believe you are correct in that you can push the temps to 85 degrees with LED's but only if you have a proper vapor pressure deficit. At 85 degrees F, you need a humidity level of approximately 70 percent for the plant to use all the light.

In the wintertime, it is really dry here, I don't get my flower tent humidity much over 60% so I've stuck with the standard 78-82 degrees with no issues so far this winter. Last summer, I had temps up to 85 degrees F in flower and the plants did well but of course there was much higher humidity. I did get a little bud rot but I caught it in time to avoid major issues.

Personally, I would much rather be a little conservative with temps and avoid issues, rather than push it too far and ruin a good crop.

Wizzlebiz said:

All info I have read, come across, and been informed here has been mid 80s with 86 degrees / 30 Celsius is the target.

LED lack the IR light to warm the canopy to proper levels. Without the higher temps the plants can't transpire. This is during veg.

During flower I was informed 82 is the target.

Click to expand...

I seen and read the same. Tho in there I also seen that above 85F Co2 should be used. Then you can tread into the 90's.
I try to stay in good vpd.

Wizzlebiz said:

What temp would you suggest for a LED setup say like a Mars hydro or a Spiderfarmer? And why?

@harrythehat
@Homegrown Hero


Thanks RIU

Click to expand...

27 to 28c is the target day temp. 20c is fine at night. Lower temps for last 2 weeks to 21 to 23c

I don't run Mars or Spider, with my LEDs I shoot for 82-84F leaf surface temp.

Wizzlebiz said:

All info I have read, come across, and been informed here has been mid 80s with 86 degrees / 30 Celsius is the target.

LED lack the IR light to warm the canopy to proper levels. Without the higher temps the plants can't transpire. This is during veg.

During flower I was informed 82 is the target.

Click to expand...

Another thing I don't like to do is swing my temp everyday by more than 10F between day & night. I run 70F at night, so I try to stay just under 80F.

HydroKid239 said:

I seen and read the same. Tho in there I also seen that above 85F Co2 should be used. Then you can tread into the 90's.
I try to stay in good vpd.

Click to expand...

Same with VPD. 86 degrees and 75% rh. It never gets higher than 86 and never lower than 82.

It depends a little on your growing method. I run my hydro tents colder than my soil tents because that's what they like. When the plant self regulate temperature in Aero it's typically at 75F leaf temp. Plants perform best at about 77F room temp in hydro. I try keeping my veg tent with soil plants at 80F.

Soil grows and coir needs more heat to grow optimally. Best thing is to look at the plants and how they respond. There's to many variables for anyone to fully say what's optimal for your grow. Plants grown under LED's may need supplemental magnesium in their feed depending on your nutrient line and mineral content. Cheers!

I have only run my HLGs over soil and promix, but the sweet spot for me seems to be 80 to 84 with an rH in the low 60s. I know that doesn't exactly match up with what the VPD charts say are ideal, but it works best for me. If I up my rH much above that I have problems with transpiration and nutrient uptake getting wonky and if I let the temp get much lower then 80 the plants get droopy, growth slows, and signs of calcium deficiency start to appear. Luckily, for most of the year, my lights just tend to keep my tents in that range without having to do much.

Maybe this can help you a bit

I can't settle this, as I don't know what the temp in my space is. I can say that I don't heat it, so the temp with the light off is 22C, same as the house. The light would warm it up some as it is enclosed. It's also the same humidity as the house which is about 35%. We have a dehumidifier in the basement that is set to 40% and hasn't turned on in two months.
The spiderfarmer lights are supposed to have IR diodes, so I don't know if you would have to raise the temp.
I guess I'll find out.
As I've said before, people sometimes yell at me saying what I'm doing will never work, and my plants will die. I just smile and say "okay". I pay attention to what they say, and if they seem to be right I put it into practice, but what is necessary for me or you might be optional for someone else.

Jimbo the Gael said:

I can't settle this, as I don't know what the temp in my space is. I can say that I don't heat it, so the temp with the light off is 22C, same as the house. The light would warm it up some as it is enclosed. It's also the same humidity as the house which is about 35%. We have a dehumidifier in the basement that is set to 40% and hasn't turned on in two months.
The spiderfarmer lights are supposed to have IR diodes, so I don't know if you would have to raise the temp.
I guess I'll find out.
As I've said before, people sometimes yell at me saying what I'm doing will never work, and my plants will die. I just smile and say "okay". I pay attention to what they say, and if they seem to be right I put it into practice, but what is necessary for me or you might be optional for someone else.

Click to expand...

My experience with indoor setups is limited as we all know.

But what I can tell you is that at the beginning I didn't believe it needed to be that warm and that humid.

Until I tried it and saw explosive growth and new growth issues dissappear.

I thought it was light intensity. But upon further review of info out there and what happens if its not dialed I found the lack of heat and humidity was causing new growth to come in shriveled.

Maybe it was a combo of light intensity and VPD needs. But the temp and humidity shift made a ton of difference.

You want a dialed temps no matter what the light source but I go night 20c day 25c

Day temp 30c with co2 because Bruce Bugbee and Suman Chandra both conclude 25-30c is ideal.

Wizzlebiz said:

What temp would you suggest for a LED setup say like a Mars hydro or a Spiderfarmer? And why?

@harrythehat
@Homegrown Hero


Thanks RIU

Click to expand...

I did homework for a couple weeks when deciding to switch to LED. I spoke to other growers I know, a few people seemed to think the Mars Hydro was a good product for the money. There’s a three year warranty... honestly, I knew it was stepping out of my element, but not in a sink-or-swim way. So far, the Mars is growing my plants faster with tighter node spacing / structure than cfl, MH and certainly HPS. Internodal growth is incredible for how young the plants are. I’m going to post my grow when it’s a little further along. If flowering goes as well as vegging has gone so far, this is going to be a good light.

Wizzlebiz said:

My experience with indoor setups is limited as we all know.

But what I can tell you is that at the beginning I didn't believe it needed to be that warm and that humid.

Until I tried it and saw explosive growth and new growth issues dissappear.

I thought it was light intensity. But upon further review of info out there and what happens if its not dialed I found the lack of heat and humidity was causing new growth to come in shriveled.

Maybe it was a combo of light intensity and VPD needs. But the temp and humidity shift made a ton of difference.

Click to expand...

This is my first LED grow, so I'm expecting to make mistakes. But I've seen a lot of "solid facts" fall by the wayside. I'm not saying you're wrong, just that what works for some other growers utterly failed for me and vice versa, and while some was probably grower error the first time, after a couple of tries you sometimes just have to accept that it won't work for you. I don't know what will turn out to be right in this case, and personal experiences will differ for a variety of reasons.

I will say that this isn't the first time I've grown outside of what others consider optimal temps and humidity. But I have also grown within them. Any differences affected my personal grow style to some extent. I think there is a range of conditions this plant can grow within, and that to some extent it adapts to its environment. I also think that range becomes narrower the further we get from landraces, but that's a subject for a different thread.

I grow led in veg and flower

In veg stems are stronger don't know why??
In flower temps average 27c to 30f I feel 27 is best but 30 is grand

Jimbo the Gael said:

This is my first LED grow, so I'm expecting to make mistakes. But I've seen a lot of "solid facts" fall by the wayside. I'm not saying you're wrong, just that what works for some other growers utterly failed for me and vice versa, and while some was probably grower error the first time, after a couple of tries you sometimes just have to accept that it won't work for you. I don't know what will turn out to be right in this case, and personal experiences will differ for a variety of reasons.

I will say that this isn't the first time I've grown outside of what others consider optimal temps and humidity. But I have also grown within them. Any differences affected my personal grow style to some extent. I think there is a range of conditions this plant can grow within, and that to some extent it adapts to its environment. I also think that range becomes narrower the further we get from landraces, but that's a subject for a different thread.

Click to expand...

I'm with ya on the what is apparently etched in stone is absolutely no where close to etched in anything lol.

Just going with my personal although very limited experience matched with the general consensus.