1. Slit seeding come late summer / early fall (coming up pretty quickly here). It seems like this is the way overseeding is commonly done. I would need to rent the slit seeder, spend the time doing it, and then water a couple times a day for a few weeks.

2. Dormant seeding after the soil temperature has dropped below 50F, ideally shortly before a large snowfall, just spreading on top of the existing lawn with a broadcast spreader. The idea is that the seed will lie dormant all winter and the soil will form cracks, pushing the seeds down into the ideal germination zone, and then they will germinate come early spring. Purdue University info.

I live in Northern Wisconsin, zone 3. A typical winter gets pretty cold, with some nights hitting -25F in January. But at this time we usually have a couple feet of snow cover.

My lawn is about 12,000 square feet, so I'm figuring probably 50 pounds of fine fescue seed. This will cost me about $100. Renting a slit seeder would cost me almost $100, not to mention the time involved. So dormant seeding has a lot of appeal, as even if I put down an extra 50% seed it would still be cheaper than renting the slit seeder, and would be much less work considering how much easier broadcast spreading would be and the fact that I probably wouldn't need to water as our springs are wet.

But I don't want to put down all this seed and have most of it die, and then end up wasting the money. Does anyone have experience to share with dormant seeding, especially in a cold climate like mine? I appreciate it.