Varied lighting schedule to combat light burn

[JockBudman]

Hi, so I've been struggling a bit lately with light burn issues caused by LEDs. I currently run about 60w/sqft of real draw through two seperate panels (MarsHydro 300w and a Viparspectra 225w UFO) in a 2ft x 2ft tent. The burn is mainly being caused by the Viparspectra, partly because it hangs slightly lower due to a combination of a longer hanging kit that the Mars and a lack of headroom. I also suspect it has more powerful LEDs although that's not exactly a good thing in my circumstance.

Anyway, I want to retain the good w/sqft ratio in the space, just without the drawback of the burn. I've raised the lights as high as I can and configured everything the best I can with the lowest plants under the lower hanging light but even with them sat further away than the taller plants are under the Mars (I promise, this sentence will end - don't smoke and type folks!) the Vipar plants still burn - hence why I think its the Vipar light. (See? told you it would end.)

So anyway, I burned one and had a walk outside and thought, "hey! The sun isn't the same intensity all day, lightburn doesn't happen outside, why not just try to emulate the sun?" So I've stuck the Viparspectra on a seperate timer to come on for four hours in the middle of the day, like the noon day sun.

I'm sure someone must have tried this before but I thought I'd post in case it works and that way anyone with a similar issue who sees this could benefit. Obviously though, you do need minimum two panels to make it work.
I'll update after a few days and let everyone know what happens. Hopefully this will be a success and I can get the balance between not enough and too much.

Peace

 

[Lost In Nugs]

Good idea. Alot of guys using dimmable COBs use pulsewidth modulation to copy sunrise and sunset seamless. You have done a good thing i guess.

A plant outside can get to a point where its too much light too, but like you said these times are limited to round noon and the plants deal with it for a while... If it would stay at that intensity all day they'll suffer from too much light too.

I would let the vipar on for max 90 min up to 2 hours and then shut down and repeat after a while. Check it out... Only plants will tell

Current Grow Nebula & Atomical Haze - Soil - 2'x3' Flower - 420W DIY COB - SCROG 45W DIY Veg Light

My journey seeking the light. Found some
SeymoreNugget's DIY talk - Building lights - Sharing ideas

 

[LEDBud]

For a better harvest you should use 60w sq.ft for Bud mode.

Do what ever you have to do to tighten up *both* hangers to the max and let the light shine.

I use anywhere from 60w sq.ft to 90w sq.ft with LED's at 12 inches and up to a 100w sq.ft with HPS's

A few grows ago grew 12 Oz using 65w sq.ft with 3x 175w draw led panels in a 2x4 cabinet

Mo light = Mo Bud

 

[JockBudman]

For a better harvest you should use 60w sq.ft for Bud mode.

Do what ever you have to do to tighten up *both* hangers to the max and let the light shine.

I use anywhere from 60w sq.ft to 90w sq.ft with LED's at 12 inches and up to a 100w sq.ft with HPS's

A few grows ago grew 12 Oz using 65w sq.ft with 3x 175w draw led panels in a 2x4 cabinet

Mo light = Mo Bud

I've been implementing my schedule for a while with mixed results (some improvements on one plant, no improvement/damage on a few others, small but spreading burns on two and almost a total nuking on the final one - but that's almost done so fuck it)

I'm just interested in how you manage to avoid burn? I've got more than a foot between the tallest plant and the nearest light and she's still burning. It does seem strain dependent - a few are fine vs a few are not so fine - but ideally I'd like to avoid burn at all and get the most out my lights.

Any tips? I'm totally at a loss here.

 

[LEDBud]

Does that Viparspectra panel use optics ? if not the issue might be unrelated

To manage light burn / avoid it I keep five 300w Mars Panels 8 inches above the leaves for the low and 15 inches above for the high and 12 inches for 75% of the time.

12 inches is commonly used

Maybe try plant supplements such as potasium silicate and anything else that you think might inccrease the plants health / strength.

 

[Mars Hydro]

May i know what is the size of your growing area? and how many days of your plants now?

Does that Viparspectra panel use optics ? if not the issue might be unrelated

To manage light burn / avoid it I keep five 300w Mars Panels 8 inches above the leaves for the low and 15 inches above for the high and 12 inches for 75% of the time.

12 inches is commonly used

Maybe try plant supplements such as potasium silicate and anything else that you think might inccrease the plants health / strength.

 

[LEDBud]

I am using two 600 hps in cooltubes along with the 5 mars 300's in a 4.5 x 6.5 x 7 ft high tent

 

[Icemud]

Hi, so I've been struggling a bit lately with light burn issues caused by LEDs. I currently run about 60w/sqft of real draw through two seperate panels (MarsHydro 300w and a Viparspectra 225w UFO) in a 2ft x 2ft tent. The burn is mainly being caused by the Viparspectra, partly because it hangs slightly lower due to a combination of a longer hanging kit that the Mars and a lack of headroom. I also suspect it has more powerful LEDs although that's not exactly a good thing in my circumstance.

Anyway, I want to retain the good w/sqft ratio in the space, just without the drawback of the burn. I've raised the lights as high as I can and configured everything the best I can with the lowest plants under the lower hanging light but even with them sat further away than the taller plants are under the Mars (I promise, this sentence will end - don't smoke and type folks!) the Vipar plants still burn - hence why I think its the Vipar light. (See? told you it would end.)

So anyway, I burned one and had a walk outside and thought, "hey! The sun isn't the same intensity all day, lightburn doesn't happen outside, why not just try to emulate the sun?" So I've stuck the Viparspectra on a seperate timer to come on for four hours in the middle of the day, like the noon day sun.

I'm sure someone must have tried this before but I thought I'd post in case it works and that way anyone with a similar issue who sees this could benefit. Obviously though, you do need minimum two panels to make it work.
I'll update after a few days and let everyone know what happens. Hopefully this will be a success and I can get the balance between not enough and too much.

Peace

Are you sure its light burn? got any photos to share?

The reason I ask is based on those lights, you shouldn't be getting light burn with those lights at 12" distance..

Do the lights hang directly over the plants shining directly down?

Is there a way you could mount the lights in the top corners of the tent on an 45 degree angle, so the left light is shining on the right side, and the right light is shining on the left? This would increase the distance from the light to the plant which would reduce some of the intensity, if that is the cause.

You could also try hanging some cheesecloth or another screen type material between the lights and the plants, it will dim the light intensity. (****Make sure if you do this the material is far enough from the lights to not get hot and start a fire). Even adding a piece of plexiglass between the lights and plants should reduce transmission about 15%.

Make sure you are not spraying anything on your plants while the lights are on, as this sometimes can encourage burning...

as mentioned above, potassium silicate may help the plants cope with the heat and light intensity.

Is your humidity in the appropriate range? If RH is too high, the rate of transpiration is slowed greatly as the air can't accept more moisture as its already saturated which can also lead to the plants overheating and burning. Especially if this is coupled with extremely low temperatures it makes transpiration even slower. (with LED's this is much less of a probability since LED's don't emit much radiant heat, and its much more of an issue with HPS lights). ***LED's do cause the leaves to heat up slightly but nowhere near what a HPS would do.

Are you in Veg or flowering? a plant in veg, because it has more hours of light, needs less intensity than a plant in flowering. This is called DLI or Daily Light Integral. So a plant in 18/6 needs roughly 1/2 to 2/3 of the light a plant does at 12/12.


well that's about all I can think of right now for suggestions. If you have some photos of your grow you can upload it might help all of us give even more accurate suggestions cheers and good luck!

 

[LEDBud]

Its real hard to diagnose a plant without photos of the issue.

A visual identification is needed , look online at *some* / a few Cannabis deficiency charts and compare to your plants leaves

Cal mag deficiencies are super common with LED lighting its essential that you use a supplement to fortify the Tap water or RO water

For some reason ( unknown to me ) the plants cal-mag needs go up two fold under led compared to hps.

Search for cal mag deficiencies to see if the leaves have the same brown dead spots on it.

I've been implementing my schedule for a while with mixed results (some improvements on one plant, no improvement/damage on a few others, small but spreading burns on two and almost a total nuking on the final one - but that's almost done so fuck it)

I'm just interested in how you manage to avoid burn? I've got more than a foot between the tallest plant and the nearest light and she's still burning. It does seem strain dependent - a few are fine vs a few are not so fine - but ideally I'd like to avoid burn at all and get the most out my lights.

Any tips? I'm totally at a loss here.