Led - watt per square foot?

[Aqua Man]

I had a laser heat gun few days back if tried lead temps 75-80f, now today if Been testing leadf emps 80-85

My veg temp t5 cfl lead temps are 77-79 the grow well but also todsy if upped to 80-85 room temps 83-85f

First make sure its set to surface temp... then get lighting figured out and then give it a few hours to stabilize. If leaf temos are still a bit high first ask yourself does it look like i have adequate airflow if not then adjust and give a few hrs. Then if still check humidity and make sure vpd is good if RH is to high the wont transpire as much which also cools the leaf from evaporative cooling. So dial in the VPD. Then if atill high consider lowering temps or increasing exhaust...

lol if it sounds Ike a massive balancing act It is and many ways to make adjustments. Let me try and make it simple. If you can't get it in line after doing this then let me know and we can work alternatives.

First set light intensity.
Clones 5k lux
Seedlings 10k lux
Veg 15-45k (start at 15 and increase by 3-5k every few days to a week to a max of 45k)
Flower (start at 45k and increase as above)

Next look the VPD thread I have it suggests KPA (kilopascals) for different stages of growth. Use the calculator or download an app for it that takes leaf temps into account (lots out there)

Then make sure leaf temos are 75-80f

If not check airflow

If still and issue hit me up.

 

[Aqua Man]

View attachment 1028789
Note ready for tomorrow test ;)

Aguat man I know I'm going on But what do you recommend for light off temps?

Lighta off temps 10f cooler. 85 leaf temps would be with co2 supplemented rooms with silica being used

 

[Aqua Man]

Very good point! Thank you for mentioning that..So how many degrees would you say a leaf temp could differ from room temp? I've been trying to work in a general range and not go nuts trying to hit specific numbers...for instance in veg 75 to 80 deg with 65 to 70 rh and flower 70 to 80 deg and 60% rh until the last 2 weeks. Trying to just stay in that blue shaded area of the chart. How much can actual leaf temps throw that off ? Genuinely asking not sarcasm...

Up to 10f different i have seen as much as 8f difference personally. Also if your plant are good then don't worry... remember these are optimal conditions. The concern when not using leaf temos is about humidity running to high and having mold ofmr fungal issues

 

[Aqua Man]

just wanna say with VPD its a goal you don't need to be exact and plants will still grow when outside the ranges... so don't make the assumption it's gospel and you must be perfect about it

 

[Aqua Man]

going to point out also humidity if possible being 10-15% lower at night is not an issue and good practice. Plants don't transpire at night so VPD is not needed at night. But the lower humidity at night will lower the risk of mold and fungi.

 

[Ph 007]

Lighta off temps 10f cooler. 85 leaf temps would be with co2 supplemented rooms with silica being used

So if my day is 82-84 85 max max
Then set my night temps to say 73f min

 

[Aqua Man]

So if my day is 82-84 85 max max
Then set my night temps to say 73f min

That works.. haha I won't start going into temp differentials but yeah 5-10f diff should be good.

Again I cannot stress enough these are guidelines/ideals not rules so you have wiggle room and strains differ a bit in thier preferences

 

[Ph 007]

going to point out also humidity if possible being 10-15% lower at night is not an issue and good practice. Plants don't transpire at night so VPD is not needed at night. But the lower humidity at night will lower the risk of mold and fungi.

Yes mold a a gir mate haha, always hight humidity at niht i have , when i got this led running Smooth I'll be fixing night humidity

These u got in veg was day temps 77-78f lead temps 75-79f few hours ago I upped room temps to 80-83 and looked better but maybe just a tad got leds starting show funny signs just a tad, think lead temps was 82-84f

look good tho, i just dropped day yemps down now to 78-80g
Humidy is 60-80% at room temps 78-80f

 

[Ph 007]

Aquar man you a legend mate, I'm im nearly getting the leds temps spot on.

My first grow led was soil 4 plants room temps 75-78f plants looked like shit all leaves yellow all the stem where super purple hardly any green but had 5 of a plant I have had less since with healthy plants crazy, I got.loads deficcianys with below 82

 

[Aqua Man]

Aquar man you a legend mate, I'm im nearly getting the leds temps spot on.

My first grow led was soil 4 plants room temps 75-78f plants looked like shit all leaves yellow all the stem where super purple hardly any green but had 5 of a plant I have had less since with healthy plants crazy, I got.loads deficcianys with below 82

No legend here dude just a plant loving broken semi old man... with lots of time on my hands.

 

[Ph 007]

No legend here dude just a plant loving broken semi old man... with lots of time on my hands.

A superhero in my eyes, aqua man haha

 

[Ph 007]

A superhero in my eyes, aqua man haha

Broken semi old man lol I'm 35 I feel broken most days hate so see 40 50

 

[Aqua Man]

A superhero in my eyes, aqua man haha

I hate super heros... true story lol. I didn't know aqua man was a super hero when I used this name even my wife laughed at me when I told her.

 

[Ph 007]

I hate super heros... true story lol. I didn't know aqua man was a super hero when I used this name even my wife laughed at me when I told her.

I know this already mate I read a old post months ago about you saying about aquar man and didn't know about the super hero brilliant

 

[aaxiii]

I don't know if it is because my tents are downstairs in the breakfast/den type area of the house but I run 150whps or 250whps lights with leds in hybrid combos in my tents. I only have two fans inside, a fan blowing in at the bottom and a fan sitting on the holes on the top expelling the air, and I never have a heat issue. Only 3x3x6 tents though. The tents are in a large open well ventilated area. I tend to run warm myself so we always run the AC. I have never seen them go over maybe 85 degrees even through the recent heat wave.

The AC in summer cools them with the house and the heater heats them in the winter. My bill was massive every month so I had to cut corners where I could. I realized that for me environment sort of worked it self out with this method and it was a big deduction from my bill. My boyfriend was starting to wince at the mailbox...he smokes but does not participate in the grow but he does pay the bill so I had to fix something without losing yield. The Sun shames every light I have ever used. I adore him.

From reading lot of posts in this forum I am finding out that I am unconventional and lazy. (My assessment) I never go over the strains' yield estimates too often but I never go under. Unless I doing crazy experiments on them and train them in a hurry or not at all.

I feel bad saying I never have a heat issue because my state is currently on fire. The smoke has actually blocked out the Sun and his much loved rays from my girls outside. But inside...weeeeeeeeeeee!

My AZ Cardinals might not even play tomorrow because SF air quality is almost at 200. Which is going to kill my fantasy match up.

 

[Ph 007]

I don't know if it is because my tents are downstairs in the breakfast/den type area of the house but I run 150whps or 250whps lights with leds in hybrid combos in my tents. I only have two fans inside, a fan blowing in at the bottom and a fan sitting on the holes on the top expelling the air, and I never have a heat issue. Only 3x3x6 tents though. The tents are in a large open well ventilated area. I tend to run warm myself so we always run the AC. I have never seen them go over maybe 85 degrees even through the recent heat wave.

The AC in summer cools them with the house and the heater heats them in the winter. My bill was massive every month so I had to cut corners where I could. I realized that for me environment sort of worked it self out with this method and it was a big deduction from my bill. My boyfriend was starting to wince at the mailbox...he smokes but does not participate in the grow but he does pay the bill so I had to fix something without losing yield. The Sun shames every light I have ever used. I adore him.

From reading lot of posts in this forum I am finding out that I am unconventional and lazy. (My assessment) I never go over the strains' yield estimates too often but I never go under. Unless I doing crazy experiments on them and train them in a hurry or not at all.

I feel bad saying I never have a heat issue because my state is currently on fire. The smoke has actually blocked out the Sun and his much loved rays from my girls outside. But inside...weeeeeeeeeeee!

My AZ Cardinals might not even play tomorrow because SF air quality is almost at 200. Which is going to kill my fantasy match up.

My electric bill has gone quit wloy using led because the need for heating the tent lights on with a oil radiator,

I'm planning myself to try hybrid room
Led and hps in a 4by4 tent
I plant to have 1 400 watt hps in middle of the room and 2 led quad board 1 either side of the light
So be 1 led board 1 side dimmed to 100 watt, then a hps 400 watt theb another lead board 100 watt so it be back to my usual electric bill I had try ning 1 600 watt hps and I think I can then run my room cooler back to 75-78f as it's now getting higher leaf temps from the 400 watt hps

 

[Gduptreedup]

I been dimming my dimmers down 1 quarter from max,
Iv been dimming down from 240 to 200watt I use a measuring thing you put put the plug, reason for the dimming 1 they seem a little to bright and 2 Iv been needing to heat my room lights on to room temperature to 85f
To get leaf temprutute right

If also been testing ight temps at 75-76 but last 2 days in testing night at normal 72f min.
Do you know anything about led and temps, If tried lower temps the do not like it at all,
I think I got day temps right now just need to perfect night temps.

Room at 85f with my led gives me same leaf temprutute as a hps light, so really it makes sense to keep night at same as hps would be.
If read night with led should 76 if the day us 85 that

I might go back to go hps as.it acutely might be cheaper to run as with led I'm needing to blast heaters in the day,.

I might even do this
Insted of my.usually 600 watt hps
Have 1 x 400 watt and 2 leds , one either side of the 400 watt hps so I could run baxk in hps.temos at 75-78f
So total of all then 3 light is 600 watt

And you said you rumbled on lol

Night temps 10 degrees cooler than day

 

[Nectarivorous]

She

30w per sq ft is for flowering you won't need to run that in veg.

More importantly is the intensity and coverage. About 600 ppfd max in veg for 18/6 and aboit 900ppfd in flower 12/12. You need to take into account the number of hours the lights are on when considering intensify.

Notice 900ppfd in flower (without co2) then 600 in veg. Then look at the hours... in flower you are running 1/3 less hours so you increase the light intensity by 1/3 to keep the DLI similar.

So if you have an android download light meter by my mobile tools dev and for veg 15k-45k lux and flower 45-65k lux. Always start at the low end and work up. Adjust height and intensity to get the most even coverage at the ideal intensity.

With 30w per sq ft you should have no trouble hitting those numbers

30w per sq ft is for flowering you won't need to run that in veg.

More importantly is the intensity and coverage. About 600 ppfd max in veg for 18/6 and aboit 900ppfd in flower 12/12. You need to take into account the number of hours the lights are on when considering intensify.

Notice 900ppfd in flower (without co2) then 600 in veg. Then look at the hours... in flower you are running 1/3 less hours so you increase the light intensity by 1/3 to keep the DLI similar.

So if you have an android download light meter by my mobile tools dev and for veg 15k-45k lux and flower 45-65k lux. Always start at the low end and work up. Adjust height and intensity to get the most even coverage at the ideal intensity.

With 30w per sq ft you should have no trouble hitting those numbers.

Side topic haha. What's with all the old school guys who like to give people shit for buying LED and saying they are inferior? Are a lot of them out of touch with the technology? Even guys in stores will talk in terms of wattage and tell you you must spend over X dollars or you're wasting your money. When I bought I sought out independent PPFD maps and worked off trying to get as much as possible in 800-1000 across the 4x4. I know spectrum and a number of other things matter but why talk about wattage when ultimately photons are the thing, just look at number of photons being delivered that are accessible to the plant, surely? Am I missing something?

 

[Aqua Man]

She


Side topic haha. What's with all the old school guys who like to give people shit for buying LED and saying they are inferior? Are a lot of them out of touch with the technology? Even guys in stores will talk in terms of wattage and tell you you must spend over X dollars or you're wasting your money. When I bought I sought out independent PPFD maps and worked off trying to get as much as possible in 800-1000 across the 4x4. I know spectrum and a number of other things matter but why talk about wattage when ultimately photons are the thing, just look at number of photons being delivered that are accessible to the plant, surely? Am I missing something?

Nope your not but some still are... watts means nothing... ppfd is everything. Spectrum is also important and the ratios are still being tested and improving.

Some really good info on spectrum and lighting in general here

Frontiers | An Update on Plant Photobiology and Implications for Cannabis Production

This review presents recent developments in plant photobiology and lighting systems for horticultural crops, as well as potential applications for cannabis (...

www.frontiersin.org

 

[Nectarivorous]

She


Side topic haha. What's with all the old school guys who like to give people shit for buying LED and saying they are inferior? Are a lot of them out of touch with the technology? Even guys in stores will talk in terms of wattage and tell you you must spend over X dollars or you're wasting your money. When I bought I sought out independent PPFD maps and worked off trying to get as much as possible in 800-1000 across the 4x4. I know spectrum and a number of other things matter but why talk about wattage when ultimately photons are the thing, just look at number of photons being delivered that are accessible to the plant, surely? Am I missing something?

Side side topic that this kind of concerns, I saw on a thread you went one further and started that even GPW is a poor metric. What do you use as your metric to determine success of grows, is it more quality of fruit such as density etc?