I wouldn't worry about it...I would say the soil I throw on top gets up to about 1/2" as well. You'll notice when it's first coming up that where the larger dirt clumps are, yeah the seeds don't come up. But by the time they get a few inches tall you can't even notice the difference.

How many 1/2" clumps of dirt per square foot are you talking about here? If it's just a few then it won't matter.

I'm going to disagree with the use of topsoil for anything except fixing a yard with poor drainage design. Casual use of topsoil for top dressing or routine use for anything is asking for problems. Eventually someone will want to haul it all away so they can get back to a level yard.

Specifically what should be on my checklist when I'm shopping for material to top dress the lawn? Are there good quality top dressing material that are available to DIY homeowners at reasonable prices to cover several 1000 sq ft? Terms "top soil" or "loam" are widely used, but once I started the actual work of overseeding (and re-seeding some large patches), I realized that top dressing is just as important as the quality of the seeds (and there is no NTEP-equivalent rating system for the soil!)

We had 2 days of heavy rain and the soil now looks very compacted. I have some seedlings breaking out, but remain concerned about the top soil that I used...

To germinate, seeds need to have moisture and be kept within a certain temperature range. They don't "need" topdressing or even soil. They will germinate just fine on a wet paper towel.

The method of sprinkling a thin layer of material on top of the seed is a means to an end - retaining moisture and moderating temperature. In this method, the main risk is putting so much material on top of the seeds that the young grass blade can't get to the surface.

Based on that, let's look at your approach so far. You've used a topsoil. That is pretty middle of the road in terms of moisture retention, but pretty good at moderating temps by shading the seed from sun and protecting it from wind. The larger chunks run a higher risk of smothering the young plants, but that will only impact the seeds directly underneath the largest chunks. Overall, I'd expect pretty good success with the method.

If you had asked before hand, I would have recommended using a finely screened compost. It holds water better than topsoil. It also is a lighter consistency so the grass has a slightly easier time growing up/through/around any chunks. It also has the added benefit of improving soil structure in the long term.

I keep reading from many on here that compost should be applied to lawns. I have just overseeded and patched all my thin lawn spots but I have never applied a compost to my lawn.

What EXACTLY are you recommending for a compost application? Brand? And where do you get it? I'm afraid I'm pretty limited as to what I can get.

Bagged Composted Manures from the Garden Centers?

How do you determine what quality is in the bag? I do compost yard waste but I really don't believe I can trust the home made stuff as I have made it since I believe there is quite a bit of weed seed mixed in. And Yes, I know that the weed seed should parish if the compost is mixed correctly but I rarely have an opportunity to mix my bin so I save it for my deep plantings of trees and shrubs.

Thanks to anyone who can help.

Thanks.

If you topdress with compost you want to sprinkle about 1/4" on top. That equates to about 1 cubic yard per 1000 sq ft. Most of the bags are 1 cubic foot, so you would need 27 of them.

Frankly though, the bagged compost is usually pretty poor quality. If you can, find a garden center or similar that composts on site and sells in bulk. That way, you can see what you are getting in advance.

Hi Bill, I spread the seeds ( and starter ferilizer) above the top soil. But with your approch the 1/4" compost goes on TOP of the seeds. I can see that being more helpful for moderating temp, retaining moisture and generally protecting the seeds, but one has to takes care to keep the layer no more than 1/4". I'm starting to see some germination. Next hurdle is the weather. According to forecast, temp can dip down to 30Fs overnight in a few days. I'm really not up for hurdling any more compost/loam. Can spreading salt marsh hay over the seeds provide some protection against frost ...? Or, do you recommend speading thin loam over the seedlings to keep'm nice and tucked in against the frost...?

Air temperature dipping to 30F is not much of a problem. Cold is only a problem if the soil temperature drops enough that it won't germinate or if it has germinated, if it gets cold enough to cause frost heaves that disrupt roots that aren't established.