This is totally nitrogen defficiency right?

I was stumped for the longest time why my plant's older fan leaves were yellowing while the stem branch growth where the buds will eventually grow looked dark green. I wasn't using any nutes so it couldn't be burn but maybe light burn? No...the top leaves were fine.


But I just read about nitrogen deficiency. Makes so much sense. The difference between this grow and my last grow where it was green the entire veg time is that I'm using more lights but no no nutes. It totally makes sense that the plant would ration the nitrogen to branches that are important while letting the sun leaves near the bottom yellow first. It's probably even more pronounced because of the abundance of light, lots of growth but not that much nitrogen.

I just gave my baby a dose and hope to see some improvement soon.