Led Newbie- Have I Cooked My Seedlings?

[Soilfoodwebguy]

This is my first post and would appreciate any opinions my 1 week old seedlings which have a slight browning on the first set of leaves and appear somewhat pale in colour. This is my first grow with LED lighting and believe I may have provided too much light intensity? Using 3x 100 watt Vero 29 cobs at 24" above at 75% power for the first 5 days but have since backed it off to 50. Have never had an issue previously with fluorescents then moving to MH after a couple of weeks.

 

[crimsonecho]

Leds are pretty powerful. How many plants you got?
If you are providing 150watts of led to that one seedling you are over doing it.
For that one seedling 20 watts is plenty.
Maybe go 25% or something. Do these cobs have lenses on them?

 

[Soilfoodwebguy]

Leds are pretty powerful. How many plants you got?
If you are providing 150watts of led to that one seedling you are over doing it.
For that one seedling 20 watts is plenty.
Maybe go 25% or something. Do these cobs have lenses on them?

No lenses but reflectors that offer 80 degrees. I have 6 seedlings under the lights. Yes I may back them off even further. Would too my light also bleach the leaves?

 

[crimsonecho]

No lenses but reflectors that offer 80 degrees. I have 6 seedlings under the lights. Yes I may back them off even further. Would too my light also bleach the leaves?

Eventually it will. All that 6 seedlings would be happy under just 50 watts at a distance. 20” inches probably.

 

[Soilfoodwebguy]

Here is my current set up

 

[Soilfoodwebguy]

Will dial it down to 25 - 30%. Are they likely to recover?

 

[crimsonecho]

Here is my current set up

You cannot turn them off individually right?
Then go 25% at 20-25 inches, watch the plants and adjust accordingly is my advice.
They look fine just a little tip burn. And your setup seems fine too.

 

[Soilfoodwebguy]

You cannot turn them off individually right?
Then go 25% at 20-25 inches, watch the plants and adjust accordingly is my advice.
They look fine just a little tip burn. And your setup seems fine too.

Great, thanks for the input....much appreciated

 

[crimsonecho]

Ah also if its 21C is what i am seeing on that temp monitor. Than it may be a good idea to bring those temps up a bit if possible. 21 is not bad, but in veg 25-26 has been better ime. Also if its 21 at lights on it must be getting a bit cold at lights out.

 

[Soilfoodwebguy]

Ah also if its 21C is what i am seeing on that temp monitor. Than it may be a good idea to bring those temps up a bit if possible. 21 is not bad, but in veg 25-26 has been better ime. Also if its 21 at lights on it must be getting a bit cold at lights out.

I agree, the lights off (daytime) don't go below 19.5c and average around 23c lights on. I'm hoping once I get them veg and add the second set of lights I can get the temps up around 25c. The LED play is completely different as with my HPS set up, it was all about getting the temps down! Just seemed to make more sense these days going LED in a 4x4 tent but need to get comfortable with them.

 

[crimsonecho]

I agree, the lights off (daytime) don't go below 19.5c and average around 23c lights on. I'm hoping once I get them veg and add the second set of lights I can get the temps up around 25c. The LED play is completely different as with my HPS set up, it was all about getting the temps down! Just seemed to make more sense these days going LED in a 4x4 tent but need to get comfortable with them.

Never used hps but i love my leds for sure. Very efficient, very long lifespan.
The low electricity bills are also important if you are trying to be discreet.

 

[Soilfoodwebguy]

I agree, the lights off (daytime) don't go below 19.5c and average around 23c lights on. I'm hoping once I get them veg and add the second set of lights I can get the temps up around 25c. The LED play is completely different as with my HPS set up, it was all about getting the temps down! Just seemed to make more sense these days going LED in a 4x4 tent but need to get comfortable with them.

First round is a big unknown as some of my grow buddies have said hit them full power in a couple of weeks while others have suggested that I won't even need 100% power with both lights 6x100 watt until I'm well into flower? I guess my approach will be less power and Increase gradually.

 

[Soilfoodwebguy]

I have a med license but still discreet. The bigger factor is Ontario has highest electricity price in North America

 

[crimsonecho]

First round is a big unknown as some of my grow buddies have said hit them full power in a couple of weeks while others have suggested that I won't even need 100% power with both lights 6x100 watt until I'm well into flower? I guess my approach will be less power and Increase gradually.

600watts of good led lights like the ones you have, would be the max you will want to go in a 4x4 imo. I am building a fixture myself right now. With cobs. Smaller cobs ran softer at 700ma. 18 cobs total. It will pull 500 real watts, after driver losses will come to 450watts (not the most efficient drivers).
600 watts could be too much or just perfect. Going up gradually would be the best idea as you said.
Seen some grow journals with 300 watts in a 3x3 with great hard nugs, seeing a 4x4 is almost twice as big 500-600 should do well.
Used 450 watts of cob+pcbs myself in a 4x4 area with 4 plants and this is the result.

When they dont like the intensity of the light, usually they curl downwards as if they are trying to cover from the light.

 

[Soilfoodwebguy]

600watts of good led lights like the ones you have, would be the max you will want to go in a 4x4 imo. I am building a fixture myself right now. With cobs. Smaller cobs ran softer at 700ma. 18 cobs total. It will pull 500 real watts, after driver losses will come to 450watts (not the most efficient drivers).
600 watts could be too much or just perfect. Going up gradually would be the best idea as you said.
Seen some grow journals with 300 watts in a 3x3 with great hard nugs, seeing a 4x4 is almost twice as big 500-600 should do well.
Used 450 watts of cob+pcbs myself in a 4x4 area with 4 plants and this is the result.

View attachment 839240

When they dont like the intensity of the light, usually they curl downwards as if they are trying to cover from the light.

Nice results. I thing going with cobs at 3500K was the best choice and interested to see how they perform from veg through to flower. I figured 4 plants is the right number for 4 x 4 as well. Thanks for all the input.

 

[Soilfoodwebguy]

I agree, the lights off (daytime) don't go below 19.5c and average around 23c lights on. I'm hoping once I get them veg and add the second set of lights I can get the temps up around 25c. The LED play is completely different as with my HPS set up, it was all about getting the temps down! Just seemed to make more sense these days going LED in a 4x4 tent but need to get comfortable with them.

 

[Soilfoodwebguy]

Hi CrimsonEcho, I just wanted to follow up and send a thanks for the tips a few weeks back. I have since raised my lights and set them to full power which has allowed me to get my temps up to around 24.5c and 20.5c lights off. Currently my lights are 50" above my plant tops and seem to be responding better over the past week.

 

[crimsonecho]

View attachment 843251 Hi CrimsonEcho, I just wanted to follow up and send a thanks for the tips a few weeks back. I have since raised my lights and set them to full power which has allowed me to get my temps up to around 24.5c and 20.5c lights off. Currently my lights are 50" above my plant tops and seem to be responding better over the past week.

Nice goin’ man. I think you can keep the lights closer than 50” now. :)

 

[Burned Haze]

I would do 16-20 inches (reflector and in veg, I would do 12-14 inches in flower with no reflectors ) away and dim the led down. A led further away is just wasting watts and promoting it to stretch instead of staying bushy/uniform.

I gradually dim up per the day/week and log it and watch how certain strains or how healthy/adopted they are make alll the difference . Point is those little things make all the end result ( I try to even measure my distance of my led to lights everyday cause that was one of my worse mistakes cause even a day off can fry/stress em)

 

[Soilfoodwebguy]

Thanks Guy,s ....just getting back to my messages and thanks for the input. Got all 600 watts at full power now and around 40 inches from tops though still paranoid to get them closer. Maybe I will drop them an inch a day until I get to 30" as they don't appear to be stretching. Just concerned that I will outgrow the 4x4 tent if I don't flip them soon topped once and transplanted a week ago in to their final pots. Also LST and seem to be taking it well.