Connecticut's climate demands that you plant certain varieties of grass seed at just the right time. Grass planted during the wrong season may never take root, but a lawn planted during the right window of time can thrive for years.
Turf grasses are divided into two basic categories: warm-season grasses and cool-season grasses. Of these, the latter is better suited to growing in Connecticut. Cool-season grasses include common varieties like Kentucky blue grass, tall fescue and perennial ryegrass. Blends of multiple varieties are better than any single type.
Cool-season grasses can be planted in early spring or early fall in Connecticut; these periods are at the beginning of these grasses' annual growth cycles. According to the University of Connecticut, fall is the better time, with prime conditions from late August through early September.
Early fall offers ideal conditions for a variety of reasons: the days are still warm enough to encourage grass to germinate, but the increasingly long, cool nights help keep the ground moist. Fall-planted grass will also have less competition from perennial weeds, most of which bloom in spring. Be sure not to delay planting until too late in fall; once October rolls around, you run the risk that your grass will not be established before winter.