What makes a leaf go yellow any way?

I have a heavley budding HUGE tree plant.
Any way, what actually makes the leaf go yellow any way?

Did it want Nitrogen? Is the plant telling me its close to done?
Should I have fed it more then once a week? (Usually 5 tbs of maxsea bloom 3/20/20)

Today I gave it budda bloom and will do so every day till flush (25% strength) rather then every other watering.

Also giving 1tbs of molasses.

Its a 2 or 3 pounder dry plant but Im thinking its yellow before its time.
It is not ripe so it will continue to thicken up?

Today was warm!

I have the same thing going on man, it's really hard to tell, it could be so many things. It could be over/under watering, it could be improper PH, Could be lack/too much of N,P or K. Hell even the sun could burn them and turn them yellow if it gets too hot out. It is hard sometimes to diagnose a yellow leaf, people always assume its a lack of N but it can get much more complicated than that.

the plant is for sure backing out the nutrients in the leafs, it thined up quite a bit but still healthy., Its neighbor is much more healthy and they are both busting out large.
But I think she could have gone a bit longer. Plants have different needs. Its one thing I learned.,

Bloom nutes have very low N content, and that'll cause them to go deficient early. It's a good idea to use some veg fert, sparingly, through the first 1/2-3/4 of flowering, just enough to keep 'em green. There's no exact feeding schedule for you to follow, so you're on your own, there. Time to learn to 'read' your plants, my friend.