SteveMcT

Why do you think there’s a nitrogen deficiency? It’s normal for older leaves to yellow as flowers mature. The new growth looks a vibrant green. I wouldn’t be adding much nitrogen this late in flower

I don’t think your light is strong enough. I’d trim off the lower 2 branch nodes, top and flip to flower in a couple weeks and see what you get. I grew the same strain a few months ago and by 7 weeks after it was big. Not too much stretch so give it 2 weeks after topping before you flip.