Spring Over-Seeding vs Fall

I've always suggested to over-seed in the fall as soil temps are ideal and the daytime temps begin to cool. You get the germination process to begin in the fall and then the lawn goes dormant for the winter.  Then spring comes and your lawn is ready to go.

This past summer (2012) we went through a severe drought and there are a lot of lawns hurting right now, especially if they didn't get over-seeded in the fall. So, do you over-seed in the spring?  You can, but it's not ideal and currently we going through a stretch of below normal temperatures. The average for right now is about 61 degrees, but for the past two weeks we've been at least 10 degrees below average.

For seed to start to germinate the ideal daytime temps need to be in the 60-70 degree range and right now we're just not getting it.

Then those of us in the lawn mowing business we're now past mid-April and in the state of Iowa not many (if any) have started mowing yet. Why is that?  Well for root growth we need temps to get into the 50-65 F degree range and for shoot growth temps need to be in the 60-75 F range and we're well below that.

Right now our soil temperatures in Central Iowa are in the low-mid 40's.

So, as much as we need our rain, which I'm very thankful for, we also need temps to warm up. Is that going to happen?  Here is our 7-day forecast (thanks to WHO-13).

There's some hope at the end of the week, hopefully that is the start of some consistent weather. If we get that coupled with the rain amounts we've received so far this Spring, the lawns will take off and if you over-seeded in the spring you should soon see positive results.  But, for future reference, plan ahead and try to have the lawn aerated and over-seeded in the Fall.