New plant possible problems?!?! Please help (pics)

I have eleven plants that are three weeks old; from seeds. Most seem to be doing great but there are three that are a bit yellow on the tips and another ones leaves are slightly curled upward. I have not added any fertilizer yet so if anyone can recommend what type of fertilizer I can add or a website I can go to so I can learn about that.

Thank you.

It looks like they're begging for some nitrogen. Does your soil have any nutes in it? Im using promix right now and my seedlings only made it 14-15 days before needing nutes.

Fox Farms liquid trio is well respected. Bio-Bizz is also good stuff. If you want to save some money you can buy Blue Mountain Organics line on Ebay. Check out the organics forum here to read the thread about them.

Also, the one with the taco looking leaves appears heat stressed. What type of lights are you using, how far away are they, and what are the temps in your grow area?

In the future, if you want more help post in the correct forum. We have a forum solely for plant problems.

Those are small for 3 weeks. R those in pots or in ground? I would start a medium nute regiment asap.

what kinda medium are they in?