Yellowing leave

[Ander]

I'm about 4 weeks in veg feeding ghp e.c 1.5.ph between 5.8 n 6.2 using dimlux lights only on 600 at the moment ...leaves starting to goin abit yellow .can any one diagnose pics below

 

[az2000]

Can you take that photo under natural light? It looks like magnesium def. I'd feed 3/4 tsp/gal epsom salt.

EDIT: I was going to say k-def besause it's more toward the edge of the leaves. But, that last photo shows it more in the margins. That's what looks like mg def to me.

 

[Beachwalker]

Can you take that photo under natural light? It looks like magnesium def. I'd feed 3/4 tsp/gal epsom salt.

EDIT: I was going to say k-def besause it's more toward the edge of the leaves. But, that last photo shows it more in the margins. That's what looks like mg def to me.

Potassium was my first impression as well

 

[az2000]

I'm about 4 weeks in veg feeding ghp e.c 1.5.ph between 5.8 n 6.2 using dimlux lights only on 600 at the moment ...leaves starting to goin abit yellow .can any one diagnose pics below

What are you feeding? (Have you fed it before, anything new this time?). K & Mg can lock each other out. Too much calcium can lock K & Mg out. (According to a chart I'm looking at.).

What kind of soil? Is it rich or light? I think ec 1.5 translates to 750ppm (Hannah, 0.5 scale). For my soil and what I feed, that's pretty high. I'd be in the 300ppm range. If I fed double what I should, it would be reflected in the runoff ppm. I start having the kind of appearance you do when it hits about 2400-2500ppm. Which I think would be 2.2 ec for you. The soil would be very acidic at that point. (I don't think runoff ph is hugely accurate. But, if I was at the point of lockout, the runoff ph would show something in that direction.).

 

[Jimster]

Looks like the start of nutrient burn to me, based on the leaf curling and the dried perimeter. It looks like a Mag deficiency, but I usually expect to see more necrosis on the middle of the leaves and not the burnt appearance of the leaves. Too much heat could also cause the effect, but without the middle discoloration. The plants looked pretty good up until the newest growth, which can sometimes show increased salt/nutrient buildupI use Promix and use fairly low amounts of nutrients compared to many growers, but the plants look like they ate something that doesn't agree with them.