Help - Deficiency?

[Toilinthedark]

Not sure what’s going on here. Lower fan leaves start yellowing but the yellow starts along the center line of each leaf blade. As it progresses, there start to be spots of yellow too. Nitrogen?
Gorilla Glue #4
Outside, 2-3 weeks into flowering.

 

[Tersky]

The yellowing between veins looks like magnesium deficiency almost but the spots could be fungus which is bad https://www.growweedeasy.com/cannabis-plant-problems/yellow-leaf-spot-leaf-septoria. Not sure just going by https://www.growweedeasy.com/cannabis-symptoms-pictures

 

[9fingerleafs]

yep, looks like a calcium and magnesium issue, you need calmag

 

[az2000]

If it's only the lower leaves, I wouldn't worry abut it too much. It's not uncommon for a plant to discard unproductive leaves at this stage of life, putting its resources into building buds. It could be those leaves aren't getting enough light to be productive. If you try to correct those lower leaves, you could cause problems with the rest of the leaves which look good to me.

I wouldn't pluck leaves either. There is still stored nutrients in that leaf which the plant is drawing out. I let them drop by themselves. Or, if they're crinkly brown (or limp yellow), I will knock them off (if that's all the need.

 

[Toilinthedark]

Thanks for all the advice! What calmag do you recommend?

 

[9fingerleafs]

az has a good point, cant really see the whole plant in the pic. i like the original botanicare calmag but ive also used GH calimagic and works good, any calmag will do