(Excerpted from article on Milorganite.com by Allyn Hane- The Lawn Care Nut )
Dormant seeding is the practice of seeding the lawn late enough in the year so it sits over winter and germinates very early the following spring when melting snow soaks it, warming temps stimulate it, and nourishing spring rains keep it growing and rooting. The idea is to get a leg up on the season.
Simply put, you want to get your seed down and scratched in (important) just before the ground freezes, then hope for a snow cover quickly to follow. This window of time will be different for everyone of you so let me give you some specifics to consider:
First off, if you have bluegrass or fescue (cool season turf) but you don’t get snow cover, then I don’t recommend this practice. We need the snow to help insulate our seed from outside interference during the harsh winter. Foot traffic, animals/birds, wind or heavy rain and sun - all of these hitting your seed over winter can reduce the amount of germination you get. In the case of dormant seeding, snow is a literal blanket we need.
Next, just like with any other seeding project, you need to ensure seed-to-soil contact or you won’t get much results. This is why the ground cannot be frozen. This is also why I recommend that you only really attempt dormant seeding in areas that are less than 30% turf or even completely bare. Throw down the seed, use a metal rake to scratch it in good, and give it a light watering just to help pack everything in. From there, keep the foot traffic off and hope for the best! But remember, I only recommend this in extreme cases where you have large areas with almost no turf and you have no other choice.
If you do decide to go ahead with a dormant seeding, I recommend you get a good shot of Milorganite down sometime soon after the ground thaws in spring. You may also consider supplemental irrigation if you are not getting daily soaking spring rains. Just as with any seeding, we need lots and lots of water to get things moving, especially when it’s cold outside!
If you are unsure about trying this practice, why not choose one small spot and test it. Pick out your largest bare area and seed it in good, then next spring, hope for the best, but most of all, take notes on what happens and how you deal with it so you are better equipped the next time. And by all means, don’t miss the window next year! Get that aeration and seeding in much earlier so you aren’t playing catch up!