LED Growers - Distance from canopy ?

[atoms]

Hello,

Im on my first grow and i went for a vipar spectra 450w. No complaint with the unit so far. However i was wondering if any other grower could tell me how height their lights are from the canopy, and does it change with the age of the plant? For example, mine is 1 month from the time it broke frome the coco and if i put the light anything under 36' i see signs of light burns within 24h. By looking at the main 'trunk' of the plant its almost if its trying to get away from the center of the light (its growing at an angle). I raised it to 40' a few days ago. I was wondering if its something that is normal cause i see some setup on this page where similar lights are very close to the canopy at late stage in the growing cycle.

Thanks for your input.

 

[NAKEDGARDENER]

I’d treat an LED the same as an hps or m.h, especially with a young plant, move the light at leas t four feet away for a while

 

[DrPhoton]

If a plant is not being provided with the most ideal conditions for optimal development, then a plant can be more sensitivie to higher light intensities. Each light technology and luminaire is slightly different. So it is ideal to take references from other growers or the manufacturers recommendations. Light metric equipment is another option if you want a more accurate way for obtaining ideal height placement.

A plants stage of growth also changes how much light intensity, as leaves develop and age they are able to process more and more light. Take a look at my article on using light efficiently to see what kind of light plants can typically tolerate at each stage of growth.

 

[DrPhoton]

Campesino has these lights i believe which he hangs at around 30-40 inches during veg and around 18 inches in flowering. But il leave him to provide the exact details.

 

[atoms]

Thank you for your inputs friends. Dangerdan great articles! If it's not done alrdy they should be up there in the guides, and maybe publish a PDF with all of them for easy reference!

 

[Weed Pharma]

ALWAYS- place LED's further away than the manufacturers guide-initially and further away from the plant/canopy than you think !

 

[Greengringo]

At later stages of the grow ...like last two weeks not including the first two weeks or start counting when you start to see the flowers growth but what works for me might not work for you..so many variables to take into consideration..it depends on how much you know about the strain and it's tolerance..but be forwarned you mess around with something you truly don't understand there will be repercussions.stick to the light Manuel guide lines and you will do just fine ..exactly what dangerdan said ..I couldn't of said it better..everyone before me all have great points.

 

[Greengringo]

Campesino that was very well stated I agree with your technique for I do the exact same thing thank you for your very knowledgeable response.

 

[atoms]

With ViparSpectra 450s.

I don't start using them at all until the plants are in Final Containers (3 weeks old). I use CFLs for seedlings

So they are good strong plants by the time they get the LED light

I start them around 36" and quickly lower that over a few days to 24". I will then let the plants grow to 18" before I start raising the light again.

16-18" in Flower.

I listen to the plants and make sure that they approve.

What are the "signs of light burns", I suspect that it might be something else. How are you watering/feeding your plants?

Campesino
Hello,

i'll give you a quick background. I grow in coco 20% perlite, 5 gallons smart pot, I fertigate once at the beginning of the 18h light period and once half way. A get about 20-30% runoff . Ph from 5.8 to 6.4 ish. Under the vipar leds i can see some discoloration inside the leaf (its normal i guess? do you see the same thing?) but under normal visible cfl light they are green all the way. The 'burn' signs are mostly at the tip of the middle and lower leaves, white, slightly curved outward. Are you thinking light nutrient burn instead of light burn?

I included some pics.

1) General view under LED
2) Close up, slight discoloration under LED (normal?)
3) General view under CFL
4) Close Up CFL
5) Close up leaf CFL
6) Curl tips
7) Curl tips

 

[atoms]

Campesino my TDS meter is on the way! Thanks for your input.