I have a pretty nice lawn, but there are some dead patches. About how long will it take for those to grow back? Should I put grass seed down or do you think it will come back on its own?

If they`re biggish patches then you`d be best putting seed on them then in time those patches will blend in with the rest of the lawn. If they are small then you may find they cover up by natural means.

And if you do decide to re-seed the patches there are a few tips so that you make sure you`ve not wasted your money.

The primary one is that seeds must be planted (covered by soil) at the correct depth. With most grass seeds that depth is 1/8 to 1/4 of soil above the seed. Depth can be critical with grass seeds.

Second is that good seed/soil contact also means that the soil has good moisture and that the soil is in CLOSE contact with the seeds allowing moisture in the soil to enter the seeds. Often slightly firming the soil after planting with a light roller presses the soil tigher around the seeds thus improving the germination of seeds.

Third and a key factor in getting seeds to germinate is that the temperatures (and season) must be right for the particular type of seeds planted AND there must be adquate soil moisture for the seeds to germinate. Depending on the soil type, watering may be required for multiple times daily in order to keep the top inch or two of soil moist (not wet) for the seeds and seedlings (germinated seed plant) to grow.

I find the best combination for getting grass to grow quickly judging by my own lawn is both sun and rain alternating. the grass puts a spurt on when that happens.