Answer: You would not want to put topsoil and mulch over top of the seed, that would put the seed too deep and smother it. (Usually, the seed is spread on top of the soil surface and then lightly rolled to assure good soil to seed contact.) It is already really too late to be seeding (it would have been better in early September) so your seed may not germinate well this fall as it is since the weather is turning cold. Some may germinate now, but I would expect you will need to overseed again in the spring. The mulch (such as a light straw layer) would have helped to keep the soil evenly moist while the seed was germinating; if the soil dries out during the process, the seed will die. There is not much point to adding that once the seed has begun to grow. Since it is so late, I would hold off on fertilizing as well. Your local county extension should be able to advise you on any needed fertilizer and other soil amendments based on soil test results. Good luck with your lawn.
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