Still getting light burn on tips even at low lighting.

Pazman21 · Aug 13, 2021

Hey guys,

so growth has been really good, but as my autos get taller they are receiving a little bit of light burn at the top tips of the canopy. I even have a light meter, which is sitting at about 6000 Lux at the moment. From my research for veg 15,000 - 50,000 is optimal so I'm sitting on the very low side at 6k. I even raised my light to the highest possible position. Any tips or info would be greatly appreciated. Thanks, guys.

GreenMtnGuru · Aug 13, 2021

Plants look great - I do not see signs of light stress.

Your humidity looks to be a bit on the low side. Coupled with the heat of summer results in those very pronounced inter-veins and slight twist on the newer leaves.

A little environmental adjustment will go a long ways - other than that you are doing a fantastic job keeping those girls happy!

30roll · Aug 13, 2021

Leaves canoe, wrinkle, edges serrate with to much light.. I would max that light out asap..
Keep it watered.. I don't subscribe to letting the pot dry out completely.. It depends on the temperature and light intensity.. You have to dial it in

Pazman21 · Aug 13, 2021

GreenMtnGuru said:
Plants look great - I do not see signs of light stress.

Your humidity looks to be a bit on the low side. Coupled with the heat of summer results in those very pronounced inter-veins and slight twist on the newer leaves.

A little environmental adjustment will go a long ways - other than that you are doing a fantastic job keeping those girls happy!

Hey man, thanks a lot for the feedback, and will do. Thanks for the tips. :)

Pazman21 · Aug 13, 2021

30roll said:
Leaves canoe, wrinkle, edges serrate with to much light.. I would max that light out asap..
Keep it watered.. I don't subscribe to letting the pot dry out completely.. It depends on the temperature and light intensity.. You have to dial it in

I have a dimmer on my light, currently, I have the light as high as it will go in the tent. Would you recommend dimming?

30roll · Aug 13, 2021

How many true watts is the light??

Pazman21 · Aug 13, 2021

30roll said:
How many true watts is the light??

2000W LED for a 2x4 i know over kill. but I have a dimmer and a light meter. so I'm trying the recommended amount with the meter but still having signs of burn on the tips.

30roll · Aug 13, 2021

Your light pulls 16.5 amps from the wall???
No what is the rating printed on the driver??

Pazman21 · Aug 13, 2021

30roll said:
Your light pulls 16.5 amps from the wall???
No what is the rating printed on the driver??

It says LED power 2000w. then actual powder 395W i can link a picture if need be.

GreenMtnGuru · Aug 13, 2021

Pazman21 said:
2000W LED for a 2x4 i know over kill. but I have a dimmer and a light meter. so I'm trying the recommended amount with the meter but still having signs of burn on the tips.

Once again, 6000 lux will not stress a cannabis plant that is more than a couple weeks from seed. Your plants are not exhibiting light stress. The slight issues you see are in direct correlation with high temps/low humidity. Your plant is minimally affected and you should be focusing on nudging your environment, not your lights.

growsince79 · Aug 13, 2021

Lux meter doesn't really work with blurple light. In fact its pretty worthless. 20k would probably fry them. Apples and oranges.

Pazman21 · Aug 13, 2021

GreenMtnGuru said:
Once again, 6000 lux will not stress a cannabis plant that is more than a couple weeks from seed. Your plants are not exhibiting light stress. The slight issues you see are in direct correlation with high temps/low humidity. Your plant is minimally affected and you should be focusing on nudging your environment, not your lights.

I try to keep my humidity anywhere between 60 to 70%, and temps stay low 20s. here is another picture of the burned tips. so it may not be humidity.

Pazman21 · Aug 13, 2021

growsince79 said:
Lux meter doesn't really work with blurple light. In fact its pretty worthless. 20k would probably fry them. Apples and oranges.

well fuck lol wish I knew that before buying it. what would you suggest?

30roll · Aug 13, 2021

Burnt tips usually means more fertilizer than it could handle for whatever reason..
I've been watering with the same food for many weeks, but then I pulled a bunch of leaves and all of the sudden the plants couldn't handle the food because there were less leaves to process and breathe.. Lesson learned. Burnt tips as a result..

It's not bad at all and the plant will snap back. Just be aware..

growsince79 · Aug 13, 2021

Pazman21 said:
I try to keep my humidity anywhere between 60 to 70%, and temps stay low 20s. here is another picture of the burned tips. so it may not be humidity. View attachment 1157081

How high is the light

growsince79 · Aug 13, 2021

Pazman21 said:
well fuck lol wish I knew that before buying it. what would you suggest?

Tape measure -trial and error. Blurple lights are all different. 2' might be a place to start. Read manufacturers recomendations.

Madbud · Aug 13, 2021

+1 burnt tips shows too much nute.

GreenMtnGuru · Aug 13, 2021

Pazman21 said:
I try to keep my humidity anywhere between 60 to 70%, and temps stay low 20s. here is another picture of the burned tips. so it may not be humidity. View attachment 1157081

Your humidistat shows some pretty extreme night/day swings. Adjust your environment. The burn at the tips of your leaves says a tad too much fertilizer. Some would say that level of burn is perfect as you are just barely pushing the plant out of its comfort zone.

Pazman21 · Aug 13, 2021

growsince79 said:
How high is the light

29 inches above the canopy, and i have about 10 inches left till top very top of the tent.

Pazman21 · Aug 13, 2021

Madbud said:
+1 burnt tips shows too much nute.

hmm i have 3ml cal mag then 3ml flora bloom 3ml flora micro per 1 gallon of water. ph regulated at 6.3. then organic soil. any tips?

Still getting light burn on tips even at low lighting.

Still getting light burn on tips even at low lighting.

Pazman21

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Still getting light burn on tips even at low lighting.

Still getting light burn on tips even at low lighting.

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