As with many other landscaping projects, timing is everything when it comes to lawn work. For example, there are times you plant grass seed and nature ensures rapid germination and growth. Other times, grass seed just seems to lie there and you end up with poor results.
While success with grass seed is always directly related to adequate moisture, there are two seasons of the year in the northeastern United States when your odds for success greatly improve: Spring and Fall. Since Spring is second best, we would like to focus on the Fall lawn seeding season. Let's narrow this down further to the month of September.
Due to the growth cycle of weeds, Fall seeding faces less weed competition, creating much better results.
Fall planted turfgrass has 2 cool, favorable seasons to become established before facing summer heat.
These same principles also apply to rigorous lawn maintenance procedures, such as de-thatching and aeration. Since these two procedures qualify as "major lawn surgery," it's best to have ideal growing conditions during the lawn's "recovery period."
Generally speaking, summer weather in the northeastern U.S. is not conducive to starting a new lawn, spot-seeding or doing any type of renovation work on an old lawn.
The sun is 'high in the sky' during summer, drying out soil and discouraging germination and establishment.
Hot, humid nights create the perfect environment for many destructive lawn fungi, such as Pythium blight.
That being said, occasionally we experience cool, wet, rainy periods during the summer months when lawns will establish well. In those cases, it's still important to watch out for fungus problems during those hot, humid spells.
DON'T water during evening hours, since this promotes a wet overnight environment that will encourage destructive fungi.
DON'T over-fertilize the new lawn, since lush, succulent growth is much more susceptible to disease problems.
A few old-timers told us they like to seed new lawns during winter months, since the freeze-thaw causes a 'honey comb' in the soil surface, creating nooks and crannies for grass seed to lodge. After all, grass seed will lay dormant until conditions are right for germination and growth.
Therefore, working under this winter seeding premise, two downsides remain:
1) Finding a time when soil is dry enough to work with, and..
2) The great potential for losing soil and seed to erosion.
Summary: It's been our experience that the less opportunities you have for wash-outs the better the outcome. Therefore, try to plant lawns during a season conducive to fast establishment, and then do everything within your power to get the grass seed up and growing the first time around. No one likes 'dragging hose' or watering for weeks on end, so make your first effort count!