We've got weeds

As I mentioned in 2010: Part 2 - The Grass Project, we have some weeds growing in the midst of the new grass, competing for the space. I tried manually pulling some of them this weekend. Here's some photos of what we're dealing with:

I pulled all of these.

I pulled this one, but most were too difficult.

I pulled some of these. They had a strong smell.

Too difficult to pull.

Only found one of these and pulled it.

I'm quite certain this problem primarily resulted from originally seeding too thin as the grass is still thin in some areas. It needs to get growing in haste and hopefully fill in making a more difficult environment for weeds to grow.

In the mean time, I'm not sure what to do about the weeds. I'm guessing that these are all broadleaf weeds and probably could be killed with Roundup or some similar herbicide. I'm going to hold off for now and see what happens once the grass starts growing. In the meantime, I'll see if I can find any suggestions.