Yellow spots are forming on my young plants!

[John Holmes]

Hi, there seems to be forming yellow spots on the leafs, i have not yet added cal+mag, it just arrived in the Mail. Ive been watering them daily with quarter nutes. And im using a 18-6 400W Mh light schedule. What may be the case here you think? The bottom of the picture. Coco coir perlite

Thanks

 

[Nunyabiz]

That's a magnesium deficiency.

If you were in soil it could be a pH issue just as easily, but with coco it's more than likely just needing some cal/mag.

And a tablespoon of Epsom salts to a gallon of water with some Yucca extract as a surfactant to use as a foliar spray is probably the fastest way to fix that though.

 

[Pbass]

I think your cal mag arrived just in time @John Holmes

 

[Elvin]

Get started increasing your nutes to full strength and use the cal mag
By the way, in a nearby suburb to where I live there used to be a "John Holmes Meat Market".
When asked why he named his deli that, John shared he had that name long before that other guy was born.

 

[John Holmes]

Alright, i Will start using the cal mag! Thanks guys