Need help adjusting to LED

[Nutty sKunK]

First time using LED after using MH/HPS

I replaced a 600w air cooled MH/HPS setup with a 645w gavita 1700e pro

It’s been some learning curve! All my plants apart from 1 have calcium defs and magnesium.

My setup was pretty dialled in before the switch now I’m finding toxicity’s and deficiencies.

Was running at full power at 3ft above the canopy but seemed to be the onset of light bleaching?

Is it simply a case of too much light? Being that these lights are much more efficient and have a better footprint there’s so much light in that tent it looks like a portal to another world on the outside.

Did anyone find when switching more calmag was needed? My water contains no calmag but I’ve been doing what I did with my other set up but getting deficiencies

Ive tried different temps with no obvious impact. Temps stay around 77f day 71 nights now.

Plant is 46 days old

 

[Porky1982]

Why would a plant need more cal mag using LED??

 

[jondamon]

First time using LED after using MH/HPS

I replaced a 600w air cooled MH/HPS setup with a 645w gavita 1700e pro

It’s been some learning curve! All my plants apart from 1 have calcium defs and magnesium.

My setup was pretty dialled in before the switch now I’m finding toxicity’s and deficiencies.

Was running at full power at 3ft above the canopy but seemed to be the onset of light bleaching?

Is it simply a case of too much light? Being that these lights are much more efficient and have a better footprint there’s so much light in that tent it looks like a portal to another world on the outside.

Did anyone find when switching more calmag was needed? My water contains no calmag but I’ve been doing what I did with my other set up but getting deficiencies

Ive tried different temps with no obvious impact. Temps stay around 77f day 71 nights now.

Plant is 46 days old

View attachment 5001227View attachment 5001228View attachment 5001229

What medium are you using?

What’s your source water EC or ppm?

what nutrients are you using? What’s the Ca and Mg levels in those nutrients?

 

[jondamon]

I’ve been finding that my source water is 0.2EC 100ppm at .5 calibration and as such the level I run my nutes it hasn’t enough Ca or Mg to sustain healthy growth with 5%Ca and 2%Mg so I bump up the Calmag by an additional 0.2EC/100ppm.

source water 0.2
Calmag 0.2
Total 0.4.

Base nutes 0.4

total 0.8EC pH6 in 100% coco.

But I’ve been doing this for years not just because I switched to LED.

 

[CheGueVapo]

Lower LST leads to lower transpiration, and that consumes more nutes with the same amount of water, if the light intensity is the same.
However the need for Cal/Mag is low compared to other nutrients

Did anyone find when switching more calmag was needed? My water contains no calmag

Using Calmag is recommended when you use RO-water or collect rain-water, so that the liming buffers in the soil don't get used up so quickly.
When your water really does not contain calcium or magnesium, and what i can see from the size of the pot, it could be possible they run into defiency.

My nutrient schedule containing a calmag product states:

Calmag:
- Designed to protect the plant from possible CA and MG deffiencies
- Can be used on low fertilised substrates and hydroponic systems

Note: We recommend to use our Calmag supplement with every watering when growing with RO water or very soft water or once a week in case of noticing Ca/Mg defiency signs

Schemes exists for:
Prevention (RO/soft water) and Defiency Correction for: Hydro/Coco or Substrate
I dont list them now.

Nice looking plant! Doesnt look so problematic to me. But ya early signs of defiency. Whats that on top of the pots soil?

 

[Nutty sKunK]

Why would a plant need a more cal mag using LED??

It’s to do with the infrared heat. Since LEDs produce a lot less compared to HPs you can have very intense lighting with little heat.

The lack of heat makes the mobility of Ca/Mag lessen. There’s an article from Dutch Passion website explains it.

 

[CheGueVapo]

Thats right... the IR rises the evaporation, the lack of it increases the vapor-chill effect! But intensity matters a lot! ALso that incfluences the stomatal conductance... its complex. But the light quality is the reason (IR).

check this out:


Figure
posted on 08.10.2015, 06:13 by Jacob A. Nelson, Bruce Bugbee

Thats why I want a fixture-cooler that radiates all the LEDs excess heat to the plants as IR... for the greenhouse effect at lower light intensities with LEDs

The most mind boggling about that is that the sun is the most intense with the most IR.... look the suns curves. WHAT THE FRACK? HOW THE HELL? Get your head around that and you can build lamps +2000µmol without leave burns

 

[Nutty sKunK]

What medium are you using?

What’s your source water EC or ppm?

what nutrients are you using? What’s the Ca and Mg levels in those nutrients?

Using mainly peat with worm castings, bat guano, Dol lime and feeding with Plant Magic old timers organic nutes when the soil tires.

38ppm so really soft. Water report states minimal cal/mag

Those PM nutrients have good calcium levels I guess but need additional magnesium which I supplement with Epsom salts.

 

[Nutty sKunK]

Lower LST leads to lower transpiration, and that consumes more nutes with the same amount of water, if the light intensity is the same.
However the need for Cal/Mag is low compared to other nutrients

Using Calmag is recommended when you use RO-water or collect rain-water, so that the liming buffers in the soil don't get used up so quickly.
When your water really does not contain calcium or magnesium, and what i can see from the size of the pot, it could be possible they run into defiency.

My nutrient schedule containing a calmag product states:

Calmag:
- Designed to protect the plant from possible CA and MG deffiencies
- Can be used on low fertilised substrates and hydroponic systems

Note: We recommend to use our Calmag supplement with every watering when growing with RO water or very soft water or once a week in case of noticing Ca/Mg defiency signs

Schemes exists for:
Prevention (RO/soft water) and Defiency Correction for: Hydro/Coco or Substrate
I dont list them now.

Nice looking plant! Doesnt look so problematic to me. But ya early signs of defiency. Whats that on top of the pots soil?

Water is 38ppm and I do alternate with rainwater. So im guessing I need to run a higher base amount. I use biobizz organic calmag. Has no N in it which helps a bunch with my soft water supplies.

They are old coffee bean sacks. Helps keep the top moist so when watering comes it doesn’t shoot off top And down the sides.

 

[sweettooth]

A few chaps have touched on it already. You have virtually NO IR coming off those leds so your ambient air temps have to be nearer 30 degrees so you leaf surface temperature is what it should. LST will be about 5 or so degrees higher than your air temps under HID lighting. Get your temps up and you'll see virtually all deficiencies dissappear. I run my full led grow between 30 and 32 degrees Celsius. 86 to 90 Fahrenheit for other people

 

[sweettooth]

also something to be said that under intense led lighting plants require a higher ec or ppm??????

 

[Three Berries]

Using lower powered LEDs, < 60ww I've found they need to be pretty close to the plant. When i ran 100ww COBs I got light burn but not from the led arrays. Using 80ww FS LED now on 3 week seedlings only 6" above them. In the flower room they stretch right up to the lights.

 

[Nutty sKunK]

A few chaps have touched on it already. You have virtually NO IR coming off those leds so your ambient air temps have to be nearer 30 degrees so you leaf surface temperature is what it should. LST will be about 5 or so degrees higher than your air temps under HID lighting. Get your temps up and you'll see virtually all deficiencies dissappear. I run my full led grow between 30 and 32 degrees Celsius. 86 to 90 Fahrenheit for other people

I’ll try that. Got the space heater to plug in but doubt I could get it that high as the exhuast doesn’t recycle the air.

 

[Er3]

Led light can fool you,that light spectrum is intense. It does take getting used to. The light you have is top line good choice brother. Your going to have some good smoke thanks for sharing.

 

[CheGueVapo]

The spectrum and what the human thinks has nothing todo with the real "intensity" talking about the amount of µmols or Watts of PAR-radiation.
The exact opposite can happen too.... Leds light without green at all (the purple one) can fool your brain thinking a LED light is low intense widening your pupils... but then more of the high intense purple light, specificly more blue light, is having HAVOC on your macula! Damage is the result!

 

[Three Berries]

I just raised one light above the tallest seedling to about a foot. It was starting to get some inward leaf curl. Using my rinky dink phone and light app they are about 12k lux at the leaf top.

Here you can see the leaf starting to curl inward from too close to the light.

 

[CheGueVapo]

also something to be said that under intense led lighting plants require a higher ec or ppm??????

It is known that one should consider the water consumption to adjust the feed.
There is a lot of things that have impact, some not even regarding to the plants directly , for example how much is the pot evaporating. YOu must take that loss ointo additional account! Or you run into mineral excesses
Do you use CO² (different stomatal conductance)?
All these require to adjust the salinity of the feed. Or your minerals build up!

More water consumption for the same growth rate requires LOWER sality of feed. Thats it!

It depends on alot of things! Yes, also depends on if high or low intense light, but what exactly depends on WHAT light, does it have IR, does it have NIR? You cant just generalize because these wavelength have effects on the transpirational processes... see picture above! It is complicated! We dont understand everything yet at all! For example what is the role of NIR? How does the suns spectrum work so good at high intensities... its miracle! We dont understand half of it... but we can try to copy, and that would have a chance to just WORK!

 

[Rurumo]

Switching over to LED requires you to rethink pretty much all aspects of your grow. Other people have touched on how important temps are. I ended up getting a Lux meter to help adjust the height of my light too. I had all sorts of deficiencies I never saw before pop up during stretch, they definitely required more magnesium than I was used to giving. I gave up on organics indoors for the time being, with this light anyway-I think they would do really well in a bed or in huge pots with huge root balls that can keep up with the light. Multifeeding with Megacrop 2-part in coco made things a lot easier for me. VPD seems to matter more under LEDs too. You basically just have to re-tune everything you are used to doing under HIDs.

 

[CheGueVapo]

One thing i find funny is the meaning of LED.... "light emitting device". The HIDs are light emitting devices, dont they?
Having it been a chip doesnt mean a thing, it depends on so much, but not the way its been crafted. Still its all the same... PAR canons, but they are not the same.... White light LED is not the same than Purple-light LED..... and if you could get the same spectrum out of an iascendant or and flourescent... what does it matter!? Technically not. It's just radiation.... it does not differ. The sun is nut special, it's the same radiation.... the tricks lays in this vast wavelength bandwidth and so much energy that we have no clue about what it actually does in plants

We must try and try... so we succeed at last.

I love this song

 

[Paddletail]

Light emitting diode