Not sure what is causing leaves to die!!!

Alright. This is my second grow. I have 2 white rhinos. 1 unknown. And 1 gdp. The unknown and gdp are doing amazing as of now. But I keep coming across issues with the white rhino. Most of the sun leaves have rotted away. Like dried up and falling off. The first pic of the leaf is what it starts out and then tomorrow will be dried up and pretty much fall off. I have 2 led lights. 300w Galaxyhydro. I use fox farms nutes and soil. This is my last soil grow. Going to move to hydro and start experimenting with a scrog. I haven't fed them in two weeks because I was afraid of giving them to much. But issue is just getting worse. I'd show a pic of the after math but I already went and trimmed the bad leaves off. Any ideas? I'll answer any questions you have if it helps me solve this. I'm also curious why the bud sites seem so airy. They are 6 weeks into flower. That's from first sign of flower.

Trial and error are key to success!!!

Pretty much any nutes off at all in mid flower and the plant will start moving mobile nutrients around. Could have been a little over fed but needs to keep getting cal/mag and a light balanced feed. Fox Farm nutes run a little hot so good to use a ppm tester and know where you're at. Cheers!

Thank you sir! I've come to the conclusion that it is root bound. My nutes are fine. The ph is good. The plant is 6 foot tall in a 5 gallon bucket. From what I've researched that's only thing that makes sense! I've pretty much problem solved everything else. Not sure if I should transplant or let her go tho? Any advice there?

Dspot,
White strains are very much Mg hogs. That would be my guess. I see a little hint of that...but you're right there. You're looking at fading between the veins. Might be a little nute locked too. I see it in that dark leaf (top pic) and some in the other shots too. (interveinal chlorosis)


Like Bugeye suggested...no need for further feeding but I would definitely add some epsom salts to your water. Foliar feeding is tricky at that stage of flower but if you think you can avoud the buds...that'll give you the fastest response.
JD