CO2 grow Light burn ?

Hi,

This is the first time i'm adding CO2 to my grow but i'm seeing some yellowing in the top of my plants, i also added more light, is this beginning signs of light toxicity or some other nutrient deficiency ?

At day 25 a start adding CO2 and increased my led strips from 600watt to 780watt, the last couple days i noticed the top leaves starting to becoming more pale.
My grow space is 3,3ft by 4,25ft, i'm thinking even with CO2 maybe 780 watt is too much?

Strain: amnesia
flower day 33
night temp 71f
day temp 84f
humidity day 60-70%
CO2 1000ppm
nutrients: 900ppm/1,8ec, ph 6,0-6,4

gddg said:

Hi,

This is the first time i'm adding CO2 to my grow but i'm seeing some yellowing in the top of my plants, i also added more light, is this beginning signs of light toxicity or some other nutrient deficiency ?

At day 25 a start adding CO2 and increased my led strips from 600watt to 780watt, the last couple days i noticed the top leaves starting to becoming more pale.
My grow space is 3,3ft by 4,25ft, i'm thinking even with CO2 maybe 780 watt is too much?

Strain: amnesia
flower day 33
night temp 71f
day temp 84f
humidity day 60-70%
CO2 1000ppm
nutrients: 900ppm/1,8ec, ph 6,0-6,4

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If you're going to run co2, bring it up to atleast 1200-1500 ppm.
You shouldn't have an issue with light burn thers

i was reading that 1500ppm co2 is a waste and best is not going over 1200ppm, between 1000 -1100ppm is optimal. You would recommend increasing to 1500ppm and this wil stop the yellowing?

I'm still not totally sure it is light burn.

gddg said:

i was reading that 1500ppm co2 is a waste and best is not going over 1200ppm, between 1000 -1100ppm is optimal. You would recommend increasing to 1500ppm and this wil stop the yellowing?

I'm still not totally sure it is light burn.

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Not sure if this is your problem in the first place, but if it is, its can be hard to give plants light burn if you are at 1200 ppm.
I run it up to 1500 to ensure the whole room receives at least 1200 at a time.

Plants can absorbe a shit ton of light at that level, long as everything else is also optimal (nutes, temp, humidity, ect)

i increased the co2 to 1200ppm and decreased the light by 10% to 700watt but the yellowing doesn't stop unfortunately.
distance between light and plants is around 15 inches there isn't more room to higer the strips, i only can dim the strips more

i'm in doubt it is light burn or some kind of deficiency. I'm thinking more off light burn because it only effects the top parts of the plant, the bottom part looks healthy no yellow leaves there.

some pics off today, 4 days later, it looks like it's getting worse.

Maybe you could try feeding a higher EC? I've fed as high as 1200ppm on a non CO2 room depending on the plant. These girls could just be feed hungry bitches. Plus you are supposed to raise feed with CO2 and light intensity. They are all related.

without CO2 i normally give them around 750ppm this time with CO2 i increased by 20% to 900ppm. I'm not sure if i need to feed them more because i already see the tips off the leaves burned slightly and wouldn't they look more pale overall, not only the top leaves.?

I'm thinking light burn or some immobile element deficiency, perhabs calcium.

I'm feeding them RO water and adding general hydroponics calmag 6,5ml a gallon this is 300ppm so not sure if calcium deficiency is possible.

hope someone can help who recognize this symptomes?

gddg said:

without CO2 i normally give them around 750ppm this time with CO2 i increased by 20% to 900ppm. I'm not sure if i need to feed them more because i already see the tips off the leaves burned slightly and wouldn't they look more pale overall, not only the top leaves.?

I'm thinking light burn or some immobile element deficiency, perhabs calcium.

I'm feeding them RO water and adding general hydroponics calmag 6,5ml a gallon this is 300ppm so not sure if calcium deficiency is possible.

hope someone can help who recognize this symptomes?

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A test to see if magnesium is you can mix Epsom salts into your sprayer and spray the girls. Come back a few hours later if they are greener then it was magnesium. Also with mag deficiency the veins look dark as the leaf lightens. With calic deficiency I find there's usually purple or rust colours spots that crop up on lighter coloured leaves.

gddg said:

i was reading that 1500ppm co2 is a waste and best is not going over 1200ppm, between 1000 -1100ppm is optimal. You would recommend increasing to 1500ppm and this wil stop the yellowing?

I'm still not totally sure it is light burn.

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Here is an article that may address your yellowing issue

as well as some info on Co2 and temps here:

Best regards.

MidnightSun72 said:

A test to see if magnesium is you can mix Epsom salts into your sprayer and spray the girls. Come back a few hours later if they are greener then it was magnesium. Also with mag deficiency the veins look dark as the leaf lightens. With calic deficiency I find there's usually purple or rust colours spots that crop up on lighter coloured leaves.

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they're already end week 6 off flower so i don't wan't to spray them. I'm not sure if it's magnesium deficiency because it only effects the top part of the plant.

TheManInTheOtherRoom said:

Here is an article that may address your yellowing issue

proper ph and your plants [Archive] - THCtalk.com - Cannabis Growing Forum & Cannabis & Marijuana Discussion Forums

ACIDITY AND ALKALINITY The pH of your medium controls the avalibility of many essential nutrients necessary to grow high quality cannabis. At low pH, there can be toxicities from iron, maganese, zinc, or copper; deficiences of calcium and magnesium; or a high sensitivity to ammonium, which is...

www.thctalk.com

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MORE PROBLEMS WITH LOW pH
An additional problem associated with low ph is high sensitivity to ammonium. nitrogen is absorbed by plants in two main forms. Nitrate and Ammonium. canabis plants are able to store large amounts of nitrate when there is excess uptake by the roots. They do not have the sdame ability to store ammonium, however, so an excess uptake is toxic. Ammonium enters the soil directly from fertilizer applications; it can also be released by the breakdown of larger organic particals. Soil contains certian bacteria that convert ammonium into nitrate in a process called nitrification. These micro organisms are much less active at low pH, therby increasing the risk of ammonium toxicity. Keep in mind that symptoms of this can vary depending on age of plant; on older plants old leaves become chlorotic and curl, while in younger plants, it happens to the newest leaves.

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interesting, i'm using organic living soil and most off te time water with ph6.0 maybe a bit too low so now i increased to ph6,5.


i've grown this clone countless times never had big problems till now. Only things i changed 12x cxb3590 at 600watt to 30x ssk-1560zge-xx-2835cr cutter led strips at 780watt, added CO2 at 1000ppm and upped my nutes from 750ppm to 900ppm.

The problems started around 7-10 days after starting with CO2 and when i turned my led strips from 600 to 780watt i also slowly increased the nutrients at that time.
First thinking light burn but i dimmed my light by 10% and still it's getting worse.
Not enough nutrients i think is unlikely because they look dark green only light green at the top parts so only thing i can think off i fed them too much which caused nutrient lock out?

i think i will give them a couple time's clean water ph6,5 no nutrients and look if they start looking better.

Here some more picture's it looks like it getting worse.

unfortunately plants got worse even after adjusting ph and ppm.

i still suspected light burn and tested the light intensity with the apogee 620 meter and found out that the higer tops where getting over 1800 umol/m2/s and the average umol is around 1800. Dimming the led strips from 780w to +- 425w still gets an average of 900-1000 umol/m2/s.

the problems started around a week after when i started the CO2 and when i increased the light from 600w to 780w.
I think 1800umol/m2/s even with co2 is just to much.

what do you think? should they take 1800umol with CO2 or is it to much?

did they make it, or what?

gddg said:

unfortunately plants got worse even after adjusting ph and ppm.

i still suspected light burn and tested the light intensity with the apogee 620 meter and found out that the higer tops where getting over 1800 umol/m2/s and the average umol is around 1800. Dimming the led strips from 780w to +- 425w still gets an average of 900-1000 umol/m2/s.

the problems started around a week after when i started the CO2 and when i increased the light from 600w to 780w.
I think 1800umol/m2/s even with co2 is just to much.

what do you think? should they take 1800umol with CO2 or is it to much?

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My question is why are you feeding while using living soil? At most you should be using simple compost teas and don’t ph anything in living soil. The co2 only made your overfeeding situation worse. That’s where your issues came from.

Lordhooha said:

My question is why are you feeding while using living soil? At most you should be using simple compost teas and don’t ph anything in living soil. The co2 only made your overfeeding situation worse. That’s where your issues came from.

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got the best yields combining my organic soil mix which contains light mix,worm compost,coco, rock dust, guano pellets, sea weed, alfalfa and mycorrhiza.
and feeding botanicare pure blend pro grow and bloom for soil, recharge, mamoth P, roots excelurator and some other stuf.
did this for years and always got around 2 pounds from this strain and my setup.
so i was hoping with co2 3 pounds


start trimming today, rock hard nugs that fry your brain

gddg said:

got the best yields combining my organic soil mix which contains light mix,worm compost,coco, rock dust, guano pellets, sea weed, alfalfa and mycorrhiza.
and feeding botanicare pure blend pro grow and bloom for soil, recharge, mamoth P, roots excelurator and some other stuf.
did this for years and always got around 2 pounds from this strain and my setup.
so i was hoping with co2 3 pounds


start trimming today, rock hard nugs that fry your brain

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Your trimming those in the picture? If so please dont