Another pic...

A closeup of the newest sproutlets kgb?

A pic of the major concern I have right now...

The pic is a bit fuzzy but that looks like dollarweed or dichondra. A selective herbicide can be used on it, but I'd wait until next Spring with a new seed lawn or atleast until after the 3rd mowing.

Well I was going to hit the new lawn with a second dose of Tenacity after the second mowing. Would Tenacity take this particular issue out?

I have no personal experience with Tenacity. Try it and see. I have had fair to decent results with WBG chickweed and clover, although dollarweed and dichondra are not listed, but again, I wouldn't apply it this year. You should also google dollarweed and compare your weed to the pictures.

Another pic of the major concern...

Another closeup but bit blurry - sorry!

Another pic

If it's all through the area that you seeded, I suspect it was in the seed.

Finally a clear picture. I'm surprised but that really looks like dichondra. I didn't think it would grow in NJ. Now I'm thinking it is larger leaves and the perspective is hard to see. If they leaves are no bigger than a dime, then it is dichondra. Compared to your thumb in the blurry picture, I'm going with dichondra (pronounced die KON druh).

Either way, since you have it now, you will have a brazillian seeds come up in the spring. Weed-b-gone at the earliest opportunity (considering your new seedlings, of course) will take it out and stop it from dropping new seeds. Then do the same in the spring. Don't rely on weed-n-feed to do this. Use a real herbicide to kill weeks and a real fertilizer to fertilize. The problem with these types of broad leaf weeds is they block the sunlight from the soil and slow the grass from spreading. You need it out.

Dchall,

How long do I have to wait to hit it with WBG? Sunday, September 30th will be exactly four weeks since I sowed the seed. Also, which WBG - I know there are a few. Will Tenacity take it out? Im due for another round of that after the second mowing. Im gonna mow on the 30th for the first time. Thanks.

Dchall, will the regular Weed b Gon work or does he need the stuff that kills clover, chickweed, etc? I'm 19 days into my reno and I've got this stuff coming up too.

Updated pics after first mow....

Pic #2

Another angle...

Side yard renovation pic....strip of green leading to fence gate was part of sod connected to back yard pool.

Pic of the weed infestation

I'd be curious for a definitive answer based on the last picture. I recently seeded and have the same coming up. I waited 2 weeks after germination before I sprayed WBG, and it did clear it out, but still a bit irked about it being in the seed in the first place. I'm 100% certain it was in the seed as it wasn't there prior to seeding, I didn't till or do anything to the soil other than lightly rought the area, and covered with peat. Hasn't shown up in any part of the lawn except the seeded area.

100% certain? Did you disturb the soil when you seeded? That can bring up long-dormant seeds, easily.