Where do you live?

What kind of grass do you want to have?

What machinery did they use to prep and level the soil?

Thanks for the response. Very good questions. I suppose that would be helpful to know. We live in Seattle, grass that we'd like to grow ryegrass. To be honest, I think we got the bottom of the barrel landscapers and no tilling of the soil happened, it's something that I am more than likely going to have to do myself, the only thing they used was a small bobcat to move the dirt, that's the extent of it other than very minimal raking. I've got buyers remorse.

Your landscapers did the right thing. You do NOT want to till that up. If you do, it will not level out again unless you bring someone back in to do exactly what your landscapers already did, DO NOT till, aerate, power rake, etc.

Now, your options for the fall planting are extremely limited. I don't think you want it to be barren because of erosion. You need to get some type of roots in there. Your best bet right now is laying down some sod because it's already established. It just needs roots to dig in.

If you really want to grow grass from seed... it's really really late. You might be able to do ryegrass right now, if you kiss and pray. I don't know how cold it is there now, or how cold it will get, but you should be able to get some of it to grow. Your chances, however, will be much greater if you plant the seed, use a roller to push the seed into the soil, throw a thin layer of compost (NOT topsoil) over it, give it a good watering, and then cover it with a germination blanket (or, a clear plastic sheet) over it for few days. This will trap the heat and moisture in there to help the seeds germinate. Check on it every couple of days. Once you seed seeds germinating, it's time to remove the germination blanket. Give it a gentle watering after you remove the blanket and keep it moist for at least a couple weeks. Again, its really late in the season for seed.

Personally, I'd go with cheap annual ryegrass for a temporary lawn --- knowing that I would be planning to seed a more permanent lawn next year. Annual ryegrass germinates faster than perennial and the seedlings mature quicker than perennial, and if it all dies in a cold snap, you won't be down much. Nothing is guaranteed to survive the winter, but it's the only shot you've got for seeding right now.

I agree with owlnsr. Everything has been done more or less right, and it's late for this project.

Using a bobcat extended what should have been a quick job (for a real tractor) into something that took a little longer, but I see you already have fencing. Could be a tractor would not have fit back there. In any case you can likely get annual rye in now. You might put a mix of annual and perennial in now hoping that the perennial will germinate over the winter and early spring. Fall is definitely the best time to seed so if at all possible I would resist the idea of seeding in the spring. If you can't resist, then seed at the earliest possible moment in the spring.

Quote "The only thing they used was a small bobcat to move the dirt, "

There are many bobcat type tractors out there. They are fitted with blades, forks for lifting and many other accessories.

One of those accessories is a box grader. I do not completely understand how they work, but I do know that when they are done using it on the lawn, the ground is level, the top inch or two is loosened up, and ready to plant grass. It seems to be a rake and blade combination, that breaks up the ground (a mini disc ?) and levels it at the same time.

So if they used a box grader on a bobcat on your lot, it is ready to plant.