Now is the best time to sow grass seed, according to horticulturists with Iowa State University Extension and Outreach. Mid-August to mid-September is the best time to seed lawns in Iowa. Late summer seeding has advantages over spring seeding – for example, grasses germinate quickly in the warm soil and once seeds germinate the warm days and cool nights of early fall promote rapid turf grass growth. According to the Extension office, the grass this time of year also has less competition from weeds due to the fact that fewer weed seeds germinate in the fall.
After seeding, the the top inch of soil should be kept moist by watering once or twice daily. With proper moisture and warm soil temperatures, the seeds should germinate in two to three weeks.