Yes, you should - flowers don't need a lot of nitrogen but they do need some ... but I'm wondering if you aren't nearing the time you need to harvest these beautiful buds (and they ARE beautiful!). Have you checked the trichs on them? I say this because the pistils are nearly all brown which is usually a good indication that the plant has or is about to reach peak... Grab a jewelers loupe or take a REAL close shot of the bud so you can see what color the trichs are... I'll bet you it's almost done...
Good luck!