I have forwarded your question to an expert in the Turf science program at the University of Minnesota, it will take about a week for her to answer. Thanks for sending in your question.

Hi, Helen. Thanks for sending the pictures along with your questions. If lawns were not healthy going into these last three years of drought, it's no wonder you're having trouble. The weeds I see in the photo are indicative of dry soil and especially the knot weed is very invasive. Crabgrass, clover and ants can be dealt with. Follow directions below for weeds, and pick up a granular ant killer that you can get at any hardware store. Ants are also indicators of dry soil.
Here's where I'll start.
1. Get a good soil test done, one that tells you about nutrients, soil texture, and micronutrients. Specify micronutrients when you order, this is not always done. Three options (but not the only ones) are Soil RX, Yard Mastery and the UMN Soil Test Lab https://soiltest.cfans.umn.edu/ . Use the results to find the appropriate soil amendments you'll need and fertilizer for the spring.
2. Next week or as soon after as the heat allows, treat the weeds. The ground needs to be free of weeds. Triclopyr and Trimec will take care of these weeds. Don't wait longer than the next week or so or your new grass seed will not take.
3. Wait the length of time on the labels, up to 3 weeks. If there is regrowth - respray and wait. Watch the calendar -- the seed I'm going to recommend should go down no later than September 15th - BUT if there are weeds, do not seed the lawn, treat the weeds until the ground is clear.
4. If the ground is clear by September 15th, get a good brand of Turf-type tall fescue and Kentucky Bluegrass mix. One example is the Tuff Turf mix by Twin City Seed. This is a local company that only sells the best-rated grass seeds from national trials. You can purchase this from them directly or Beisswengers Hardware or Bachmans. JRK is sold by Gertens, and I'm sure you will find that a decent seed as well. For more location choices check out the Turf Science website at the U. Don't spend money at the local hardware store, the seed is typically the poorest rated.
Kim Sullivan UMNTurf Science Group

Updated Response with more information


Hi, Helen. Thanks for sending the pictures along with your questions. If lawns were not healthy going into these last three years of drought, it's no wonder you're having trouble. The weeds I see in the photo are indicative of dry soil and especially the knot weed is very invasive. Crabgrass, clover and ants can be dealt with. Follow directions below for weeds, and pick up a granular ant killer that you can get at any hardware store. Ants are also indicators of dry soil.
Here's where I'll start.
1. Get a good soil test done, one that tells you about nutrients, soil texture, and micronutrients. Specify micronutrients when you order, this is not always done. Three options (but not the only ones) are Soil RX, Yard Mastery and the UMN Soil Test Lab https://soiltest.cfans.umn.edu/ . Use the results to find the appropriate soil amendments you'll need and fertilizer for the spring.
2. Next week or as soon after as the heat allows, treat the weeds. The ground needs to be free of weeds. Triclopyr (preferably) or Trimec will take care of these weeds. Use Quinclorac on the crabgrass or hand-pull. If there is quackgrass - and I can't tell from the pictures, you will need to use Glyphosate on that. Don't wait longer than the next week or so or your new grass seed will not take because of residual chemicals in the soil.
3. Wait the length of time on the labels, up to 3 weeks. If there is regrowth - respray and wait. Watch the calendar -- the seed I'm going to recommend should go down no later than September 15th - BUT if there are weeds, do not seed the lawn, treat the weeds until the ground is clear.
4. If the ground is clear by September 15th, get a good brand of Turf-type tall fescue and Kentucky Bluegrass mix. One example is the Tuff Turf mix by Twin City Seed. This is a local company that only sells the best-rated grass seeds from national trials. You can purchase this from them directly or Beisswengers Hardware or Bachmans. JRK is sold by Gertens, and I'm sure you will find that a decent seed as well. For more location choices check out the Turf Science website at the U. Don't spend money at the local hardware store, the seed is typically the poorest rated.
5. Folllow the directions here for prepping and seeding your lawn: https://extension.umn.edu/lawn-care/renovating-lawn-quality-and-sustainability. Clear the weeds, hard rake the soil to create furrows, drop the seed, add peat, or a soil mulch lightly over the top of the seed and add a seed-starter fertilizer. Cover with a seed blanket and start watering. 10 minutes 3 times a day for 2 weeks, then start backing off to a couple times, then once a day. Don't stop watering on a regular schedule until the soil temperature drops.
6. Your alterative if you cannot seed by September 15 is this. Wait until around the 15th of November. The soil's going to be around 40 degrees. Prep the soil as above, put down the seed, cover with the soil mulch and leave it alone. No fertilizer, no watering. This is dormant seeding. In the spring do NOT add any weed control - that should have been done in the fall before seeding. It will kill the newly seeded grass if you do it in the spring.
7. Avoid the problem we had this year - 2 weeks after the frost came out of the soil, we had 85 degrees. All the fall and dormant seeded grass died - it was too hot for the young grass to grow. So - watch the weather. Start watering early rather than late on a regular weekly schedule as soon as it starts to warm up.
That covers it. It's work, but it will be worth it.

Good luck with your project and be patient.

Good luck, cooler temps should make your job easier.