Cool-season grass types include fescues, ryegrasses and bluegrasses. Gardeners living in the northern regions of the United States plant cool-season grass types because their climate favors a long growing season. Cool season grass planted in climates receiving hot summer temperatures go dormant or die. Plant cool-season grass when soil temperatures promote their germination and root growth.
Seed cool-season grass types when soil temperatures dip below 40 degrees, according to gardening Julie Day for Danny Lipford. Check your soil temperature by making a pilot hole 6 inches deep in the lawn. Press a soil thermometer inside of the hole. Avoid allowing direct sunlight to hit the soil thermometer. Check the soil temperature both in the morning and in the afternoon. The average of both temperatures gives an accurate reading.
Prepare the soil at the end of the summer for fall planting. Remove all weeds from the planting area with an herbicide containing glyphosate. Glyphosate prevents weeds from producing proteins, killing them within days. Pick a dry day for spraying the weeds so that the foliage absorbs the toxins. Glyphosate leaves little residue in the soil. Till the dead weeds. Break up the first 6 inches of topsoil, so that grass seeds can establish strong root systems. Wait five to 14 days before seeding the lawn after spraying the glyphosate, suggests the University of Minnesota.
Apply a starter fertilizer high in phosphorous. Use a starter fertilizer with a NPK amount of 5-10-5. Spread it at a rate of 20 lbs. per 1,000 square feet. Work the fertilizer into the first 6 inches of soil. Broadcast cool-season grass seeds over the lawn. Cover the seeds with 1/8 inch of compost. Watering the area promotes germination, keeping the soil moist for a week. If the grass seeds dry out, they will not germinate.