Dying hair with chamomile tea? Plus will drying under lamp instead of sun work?

I really really want blonder or lighter ends on my hair, so say if I put 7 tea bags, I know its a lot, but will it really do the trick? Or will it be soo much that it will turn darker? I tried it before with 3 bags and ever so slightly did it work. I have dark brown hair. Plus instead of drying in the sun can I go under my lamp? I live in England and it’s hardly sunny, all of this week is gonna be raining. This lamp makes a kind of burning smell in like 30 seconds but its normal. Thanks for those who answers. 10 points for the most elaborate answer. 🙂