When it a good time to interseed or seed a lawn?

Answer 1

Grass seed can be planted in spring, around Labor Day in the fall (before September 15) or just before winter sets in. The seed needs to be worked into the soil just slightly with a garden rake

Answer 2

There are two terms commonly referred to when seeding a lawn:
Seeding, which generally refers to a completely fresh lawn but is often used interchangeably with:
Overseeding, which refers to seeding OVER existing turf.

Any time in early spring or early fall is a good time to overseed, but fall is by far the best time. The earlier in fall the better, but the hottest of summer has to be gone, so mid-to-late september, and october are generally good as the fresh grass should finish germinating just in time for winter.
As a rule, November is best left alone as grass will incompletely germinate, but December tends to be a good month as most seed will not germinate but waits until first thing in spring.
So, seed in SOD (September, October, December).

In addition, I highly recommend Core Aerating the turf, as doing so will at least double the germination rate. You may further wish to apply a starter fertilizer, some lime (calcium-magnesium carbonate) and perhaps some gypsum (calcium-sulfate dihydrate) to help make a BIG difference.

Before applying the chemicals, I might recommend a soil test.

Answer 3

may 21. trust me. it makes the grass greener on the other side.