I "third" the other two. You might consider going with a deep mulch made from a shredded material. It will be soft on the dog's feet, absorb everything he can give it, should never smell bad, and should never get muddy. By deep I mean at least 5 cm and as much more than that as you can afford. 10 to 15 would be fine. Mulch, being an organic material, will support all the microbes you need to cover the smells of doggie waste materials.

I think your idea of mixing them is good. Plant the "sunny location" mixture in your sunny areas, the shady in your shady areas and then mix the two together and spread that in the transition between sunny and shady areas in your lawn. Please be aware that Fall is the prime time for seeding a lawn. If you do it now, you will have limited results and may choose to overseed again in the fall. In the meantime, strengthen your lawn as much as possible by eliminating weeds, properly fertilizing, mowing, and watering. Cultural practices are probably more important than choice of seeds for a descent Pennsylvania lawn. Bill Hill

Kentucky Bluegrass grows well in Pennsylvania. It spreads by rhizomes and stalens and is considered self repairing. Since you are going to purchase seed, I suggest buying the best quality you can find. Galaxy brand is widely available for purchase on the internet. It is considered an elite turf seed, or you could use a KBG mixture from Lesco or Scotts. You wonÂt regret paying a little extra for top quality seed. Bill Hill

You choose grass based on the amount of sunlight your lawn receives. There are grass mixes meant for full sun or shady areas. If you wish to get a more specialized grass, it means you would have to source them from areas other than regular hardware stores. The types of grass you may need is what is used in golf greens which are also full sun. Perennial rye grass perhaps,.. anyway consult the internet on selections.