Using Crabgrass Preventer - Without Food (Year 2)

Nat added this bag that you see at the top of this post to one of her recent orders from Amazon.  It is a bag of Scott's Crabgrass and Grassy Weed Preventer under the "Halts" product name.  It does NOT have lawn food in it - which is fairly uncommon in most crabgrass preventers.

You can find this stuff here at Amazon (this is NOT an affiliate link.  I don't do that...) for $16.99.

I used this same product last year - and sought it out because of the fact that it doesn't have lawn food in the mix.  Last year, I held off on feeding my lawn until Memorial Day and I'm thinking that I'm going to do the same.

I laid out my full 2020 lawn care plan here in this post from February.  In that post, you'll note that I'm calling for an application of this pre-emergent in "April" versus "mid-April".  And that's because that I'm going to turn to - once again - Michigan State University and their "Growing Degree Days" tracking/calendar tool.  I wrote about it last year and how they track the right time to apply products based on your own zone.  Here's a link to my zip code that shows we're still early for pre-emergents. 
Here's a look at how the maps looks this week:

You can see that the "Optimum" window - in the green bar is down in Southern Illinois and Missouri and Kentucky.  The "Early" window has reached about to Champaign in Central Illinois.  The tool is forecasting out to just the 17th now and shows how the numbers are creeping up.  I'm guessing that by the 24th, we'll be in the "Optimum" window.  I'll keep an eye on the calendar and get my stuff down on time.  I have only put this product down on the backyard - in the far reaches of our yard.  But, I'm wondering if I should be adding it into the mix now that our sod has matured.

One other thing to note:  Check out the photo of the bag at the very top.  See the two different application windows they mention?  Spring - for Crabgrass.

But...also Fall.  And they specifically call out Poa Annua.  Interesting.  I'm pretty sure I'm dealing with some Poa Annua - or perhaps Poa Trivialis.  More to come on that, but maybe I should be thinking of putting down this stuff twice a year?