"Weed and feed". By the nature of its wording...the 'weed' refers to the mix having a herbicide in its make-up.
You applied a weed killer....then applied grass seed--which the herbicide will kill.
Usually, we kill the weeds, then wait a respectable time before we apply grass seed
I'm afraid, depending on the strength of the herbicide the grass seed will not produce anything.
So, acctept that and plan on re-seeding later.

I would suggest you keep up with a watering program and I suggest you feed your lawn by putting down a layer (1") of compost or good cattle manure.
This will feed the bacteria, increase the organic matter to encourage moisture retention.
After seeding, this 1" layer will feed your lawn for many weeks and encourage strong roots.

The layering of 1" of compost over lawns is encouraged to be repeated every spring (if not every fall) to ingest more organic matter into the soil---thus encouraging more worms to come and stay, and encourages moisture retention.

Hi Courtney,

Unfortunately the seed you already put down is not going to germinate. But it sounds like you know that.

I think your idea of top-dressing with 2" of soil has the potential to work as long as you don't soak the lawn so much that the herbicide mixes with the fresh soil (water soluble). You also need to really put down 2" of soil (are you sure you realize just how much dirt you are talking?). The problem though is Scott's typical weed & feed has 2 herbicides; 1 that goes away quickly (I think at minimum you give it another week or two and hope for some heavy rains to deplete the soil from as much chemical as possible. Then you can try your approach but realize there is real chance for failure AFTER you see sprouts. If it was my lawn I'd personally put down 1" of compost evenly over the yard and wait out this spring/summer and do a major overhaul in the fall. You'll be surprised how nice dark compost makes a barren lawn look compared to the normal dirt spots.

Also when you decide to seed in the future Scott's sells a VERY good product called Scott's Step 1. It is much more expensive (I think back when I used it was somewhere between $50-60 for a small 10lb bag) than their normal line of products and you may have to go to a specialty store if your big box stores don't carry it. This is MEANT to be applied at seeding as it has a selective herbicide that prevents weeds from sprouting but allows (most) grass seed to sprout, while also giving a feeding to the new grass.

HTH

Thanks for your replies. What I have been wondering is, what is the "worst case scenario", if I do plant seed in 2-4 weeks? If the herbicide is still strong and the seeds will not germinate, are those seeds "dead" or will they germinate when the time is right? Or are they contaminated and then I wait a few weeks and reseed again? Or, what if they germinate and grow, but then die later? Could I/should I reseed after boh scenarios or would I need to remove all the old seed and start over? I don't want to overseed.

The worst case scenario is that you don't get grass now or in 2-4 weeks.

The seed will be "dead" in the sense that it won't germinate once it has come in contact with the chemical.

I think it is less likely that you get growth and then the young grass dies as the roots go deeper, more likely is you won't get growth at all or significantly less than you had planned for (say 1/4 or 1/3 germination rate, btw totally just throwing a random number out since I have no idea if anyone could give a good estimation).

You can keep trying every couple of weeks and not need to rake up the "dead" seed so no worry of overseeding as if grass does take it will eventually get the nutrients from the decomposing seed and will also supply a bit of water retention properties when watered.

If you are going this rate and plan to seed after putting down soil I would make sure the chance for germination is highest. That means eliminating the air barrier when seeding and applying a light coating of soil on top of the seeds. For large plots of land the easiest way is to seed, top dress by hand or tractor/mower 1/8-1/4" with soil, apply a starter fertilzer (the grass seed only "see's" the nutrients right next to it), and then press with a roller of some sort (then lightly water). They make these for riding mowers, or you can do it by hand with a large object (sand bags work great for small areas, my personal favorite was a large inflatable jumping gym for the kids that came in a sack that I just covered with trash bags and rolled like you were making a snowman around the yard (backbreaking but faster than you would think).

This puts the seed in direct contact with the soil and helps to keep the seed in place during wind/rain that would otherwise clump the grass and leave bare spots.

Personally, I think you will be OK (as long as the weed and feed didn't contain a preemergent). Most broad leaf herbicides are foliarly absorbed that target dicots. If you are watering daily to germinate grass seed, most of the herbicide will be diluted and washed away or into the soil. None of the herbicide will get onto the new grass blades, and I'm pretty sure it isn't root absorbed. I think the herbicide companies are pretty conservative when it comes to using their products on new grass for legal reasons.