That brown on the tip is the membrane that protected the cotyledons while they were in the seed husk still.

Listen to the other advice about your general conditions, though. The 3 weeks bit worries me.
stinkyattic Reviewed by stinkyattic on . What am I doing to my plant? Here is a pic of my new seadling. The tip of the new leave is brown. I am watering it a little bit once a day. It has been this size for over 3 weeks. I am worried. Rating: 5