CalMag deficiency or light burn?

[Dirlewanger1945]

Hi, my plant is developing brown yellowish spots on the larger fan leaves. See photos.
Not sure if it’s a cal/mag deficiency or light burn. I did just add the bloom light as well as veg.
Plant is Do Si Dos from Dr. Seeds
Plant is 34 days old in veg
Light is a viperaspectra 450w led
Light is 13 inches away from the top of the plant.
Grow tent is 3x3
Growing in a 5gal cloth pot with cococoir with a 70/30 coco to perlite mix.
Coco was buffered to 5.6 and soaked in a 150% cal mag solution before transplant.
Using Advanced Nutrients PH perfect MGB 3 part at half strength
Using Advanced Nutrients Sensi cal cal mag and iron solution at 2ml per litre
I mix my nutrients in 4 litre batches. PH is 5.6-5.8 I let it vary but keep it in that range.
I water 2 times daily until I get 20% run off. Approximately 500ml for each feed
Latest run off had a PH 5.7
RH is 60-70 percent
Temperature is 25c day and 21c night.
Light is set at 18/6 schedule
I’m pretty new at this, second grow first time in cococoir.
Cheers

 

[TorturedSoul]

"Cal/Mag" is not an element - it's two, calcium and magnesium. Looks like you could have a calcium deficiency. Are you using distilled (or reverse osmosis) water? If so, there won't be any calcium in it. Even if you're using tap water, which often contains lots of Ca in it, that Ca may not be readily accessable to your plants.

The main symptom of a Mg deficiency is interveinal chlorosis, or yellowing between leaf veins, which stay green, giving the leaves a marbled appearance.

If you wish to supplement one of these elements without adding the other, you can use: For Mg, Epsom salt, which is available at grocery stores, pharmacies, and department stores that carry "vitamins and other healthcare products often found in bathrooms." For Ca, calcium nitrate, which is available at farm supply stores, (real) hardware stores that sell various fertilizer products by the pound and bag, and suchlike.

Here's a thread posted by the founder/owner of this forum that may be helpful, especially since you're relatively new at this:

Cannabis Plant and Pest Problem Solver - Pictorial

Here is a ready reckoner for Cannabis plant and pest problems. It has been put together by a master grower. I have edited for content and added to as needed. I hope you learn from this treatise. I have been doing a lot of research on sick plants and also helping out others a lot on sick plants...

www.420magazine.com

 

[Oz3]

Hi, my plant is developing brown yellowish spots on the larger fan leaves. See photos.
Not sure if it’s a cal/mag deficiency or light burn. I did just add the bloom light as well as veg.
Plant is Do Si Dos from Dr. Seeds
Plant is 34 days old in veg
Light is a viperaspectra 450w led
Light is 13 inches away from the top of the plant.
Grow tent is 3x3
Growing in a 5gal cloth pot with cococoir with a 70/30 coco to perlite mix.
Coco was buffered to 5.6 and soaked in a 150% cal mag solution before transplant.
Using Advanced Nutrients PH perfect MGB 3 part at half strength
Using Advanced Nutrients Sensi cal cal mag and iron solution at 2ml per litre
I mix my nutrients in 4 litre batches. PH is 5.6-5.8 I let it vary but keep it in that range.
I water 2 times daily until I get 20% run off. Approximately 500ml for each feed
Latest run off had a PH 5.7
RH is 60-70 percent
Temperature is 25c day and 21c night.
Light is set at 18/6 schedule
I’m pretty new at this, second grow first time in cococoir.
Cheers

Kinda like mine. I think you should give it cal/mag. Keep high powered LED or HID up about 30" off the plant.

 

[Dirlewanger1945]

"Cal/Mag" is not an element - it's two, calcium and magnesium. Looks like you could have a calcium deficiency. Are you using distilled (or reverse osmosis) water? If so, there won't be any calcium in it. Even if you're using tap water, which often contains lots of Ca in it, that Ca may not be readily accessable to your plants.

The main symptom of a Mg deficiency is interveinal chlorosis, or yellowing between leaf veins, which stay green, giving the leaves a marbled appearance.

If you wish to supplement one of these elements without adding the other, you can use: For Mg, Epsom salt, which is available at grocery stores, pharmacies, and department stores that carry "vitamins and other healthcare products often found in bathrooms." For Ca, calcium nitrate, which is available at farm supply stores, (real) hardware stores that sell various fertilizer products by the pound and bag, and suchlike.

Here's a thread posted by the founder/owner of this forum that may be helpful, especially since you're relatively new at this:

Cannabis Plant and Pest Problem Solver - Pictorial

Here is a ready reckoner for Cannabis plant and pest problems. It has been put together by a master grower. I have edited for content and added to as needed. I hope you learn from this treatise. I have been doing a lot of research on sick plants and also helping out others a lot on sick plants...

www.420magazine.com

Thank you for the quick reply. I understand that cal/mag are two different elements.
Also I am using RO water. Sill lots to learn as this is only my second grow and first with cococoir. I will check out the post you have recommended

 

[TorturedSoul]

It's a pretty good reference thread, in my opinion, and should help with reading your plants.

Good luck with your grow!