The best time to seed cool-season grass in the Northeast is in the late summer to early fall. This is when soil temperatures and rainfall create optimal conditions for your grass to grow. Ensure you seed at least 45 days before the first expected frost.
Warm-season grasses don’t grow everywhere in the Northeast, but where they do, the best time to plant them is late spring to early summer. This is because they need warmer conditions to thrive than cool-season grasses.
Knowing the best time to plant your grass gives it the best chance at flourishing.
Connecticut
The best time to seed cool-season grass in Connecticut is from August 15 to September 15, depending on the type of grass. This is also an ideal time for overseeding.
Pamm Cooper of The University of Connecticut Home & Garden Education Center says that, during this period, “soils are warm enough to ensure optimum germination, and roots will develop good depth and biomass before the hot weather arrives the next summer.”
Don’t plant grass seed outside of the mid-August to mid-September window.
“Spring seeding is almost always a failure in New England due to the shallow roots of young grass plants and hot soils coming too soon to expect a good survival percentage of spring-seeded cool-season grasses,” Cooper added.
The ideal soil temperature for cool-season grasses to grow is between 50 and 70 degrees F. Too hot, and the grasses will stop growing, and too cold they also slow down.”
As for warm-season grass, Cooper adds that Zoysiagrass is an option.
“Zoysia is a warm-season grass and grows when soils warm to 60 degrees and above. Seed this grass in spring after the last spring frost and no less than 60 days before the first frost in the fall.”.
Read more: When to Plant Grass Seed in Connecticut
Also be sure to also check out our article How to Plant Grass Seed.
The best time to seed in Maine
The best time to seed and overseed your cool-season grasses in Maine is from late August to September. At this time, the soil is warm, but the weather is beginning to cool down. There’s enough rain to keep the soil moist but not overwatered.
You could also seed in the spring, such as in early May to June (or late May to June if you have Kentucky bluegrass or tall fescue; see the chart below). However, fall is better because you’ll get significantly fewer weeds.
Warm-season grasses are generally not recommended here.
The best time to seed in Massachusetts
In Massachusetts, you should seed your cool-season grass between the third week of August and the third week of September. This allows for the least weed competition, as well as cooler temperatures and suitable rainfall. While you could also seed in late September to October, the conditions for doing so are less favorable.
“The further you move past that ideal window, the more that factors like decreasing temperatures and shorter days begin to work against you… whether you are seeding or overseeding,” says Extension Specialist and Group Leader Jason D. Lanier from the University of Massachusetts.
You could consider overseeding as slightly more forgiving. “Grasses commonly used for overseeding are also typically faster-establishing species, so they offer a bit more flexibility in the way of timing,” Lanier says.
Zoysiagrass is the only warm-season variety that will grow here, and it will create a dense, resilient lawn, but it will only stay green just three to four months of the year.
The best time to plant Zoysia in Massachusetts is mid-spring.
Read more: When to Plant Grass Seed in Massachusetts
The best time to seed in New Hampshire
The best time to seed and overseed cool-season grass in New Hampshire is mid-August to mid-September. At this time, soil temperatures are between 60 and 70 degrees Fahrenheit, which is suitable for most grasses, and there’s still enough sunlight.
If necessary, you can also seed or overseed in around early May, but only after all the snow has melted and that the weather is looking good. Follow weather reports. Your grass may need to continue growing until the warmer summer months, but it’s not that much of an issue in New Hampshire’s cool climate.
And, you guessed it, warm-season grasses are a no-go here.
The best time to seed in New Jersey
The best time to seed and overseed cool-season grass in New Jersey is mid-August to mid-September. In general, this should give your grass enough time to grow before the cold weather arrives.
The only warm-season grass option for New Jersey is Zoysiagrass. If you want to plant it, you can do so from mid-May to June. You risk injuring it if you plant it any later. The grass will go dormant and brown from mid-October until mid-May. You can overseed Zoysiagrass with perennial ryegrass in mid-September for a green winter color.
The best time to Seed in New York
The best time to seed and overseed cool-season grass in New York is mid-August to mid-September. This gives your grass time to establish strong roots before the winter. And as September approaches the state, there’s around 4 inches of rainfall, which is ample for your grass.
Warm-season grasses are generally not recommended for New York, although Zoysiagrass can survive in its hardiness zones 6a to 7b, in the southeast and the southwest. The best time to plant it is in late spring.
Ensure your grass thrives; here’s How to Grow Grass.
The best time to seed in Pennsylvania
The best time to seed and overseed cool-season grass in Pennsylvania is late July to mid-August. At this time, the soil temperature is warm enough for grasses to germinate, but no longer too warm. You’ll also have plenty of sunshine and should also have enough rainfall to sustain your grass.
You can also seed the warm-season Zoysiagrass here in the spring, from around late May to mid-June.
The best time to seed in Rhode Island
The best time to seed and overseed cool-season grass in Rhode Island is in mid-August to early October. At this time, soil temperatures are between 60 and 76 degrees Fahrenheit, which is suitable for most grasses, depending on which grass type you have (see the chart below). It’s also not yet too cold, and your grass should get enough sunlight.
Alternatively, mid-April to early June also works. Either of these periods provide your grass with the best temperatures for growth.
Warm-season grasses are generally not recommended here.
The best time to seed in Vermont
Vermont is another state for cool-season grasses. The University of Vermont recommends seeding around Labor Day and no later than the first week of September. At this time, your grass will get cool temperatures combined with optimal moisture so that it can germinate. Plus, it’s better than seeding in the spring because you’re less likely to deal with weeds. This is also the best time to overseed.
Warm-season grasses are generally not recommended here.
The best time to seed by grass type
Grass types respond to temperature and climate differently. Here’s an overview of the typical soil temperature preferences and germination times for Northeast grasses:
| Grass | Season | Soil temperature preference | Germination time |
| Kentucky bluegrass | Cool-season | 60 to 65 degrees Fahrenheit | 14 to 28 days |
| Perennial ryegrass | Cool-season | 50 to 65 degrees Fahrenheit | 5 to 12 days |
| Tall fescue | Cool-season | 59 to 72 degrees Fahrenheit | 7 to 21 days |
| Fine fescue | Cool-season | 50 to 65 degrees Fahrenheit | 5 to 12 days |
| Zoysiagrass | Warm-season | 65 to 70 degrees Fahrenheit | 14 to 21 days |
| Bermudagrass | Warm-season | Around 80 degrees Fahrenheit | 7 to 14 days |
Get a pro to handle the hard work
Still confused about when to seed your grass, or simply too busy to do it? Don’t worry; Lawn Love has pros available throughout the Northeast US. Get an instant quote.
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