Why Fall is Best for Cool-Season Grasses
"Several distinct advantages make fall the best time to plant cool-season grass seed. In early autumn, the soil is still warm from months of summer sun. This combination of warm soil, moderate day temperatures and cool evenings encourages fast germination and establishment of newly sown cool-season grass seed.
Cool-season grass seed germinates best when soil temperatures are between 50 and 65 degrees Fahrenheit. This roughly corresponds to daytime air temperatures in the 60 F to 75 F range. An inexpensive soil thermometer, available at most garden stores, can help eliminate the guesswork.
The farther north you live, the earlier cool fall temperatures and ideal planting time come. For example, Minnesotans in the Upper Midwest seed cool-season lawns from mid-August to mid-September."
Looks like I planted at the ideal time according to most articles ive found online. I mixed my seed with oats at a 1:3 ratio and broadcast spread it. Mixed it in with a drag behind an ATV. Seems to be coming in fairly well, oats are about 3 inches tall now and grass is an inch or so. I read that rye is better to plant than oats for this purpose but I wasnt able to find small enough quantities for what I needed (feed grade) and didnt want to pay 3x as much for certified seed. Will be interesting to see how tall the oats get before frost gets them.