You need to put a pre emergent down late summer/early Fall. My area in Louisiana it is no later than mid September. It is based on soil temps. You need to have it down and watered in at least a week before soil temps hit 55.2 months early is better than a day late.

There are many out there. Prodiamine is good. Dithiopyr is better. indizaflam is the best as overall control and it covers most of the weeds. They do cause root clubbing in SA so it your lawn needs to take over bare areas it will be a struggle for the grass.

Read the label for whatever you get. Put down 1/2 the max rate as stated above. Then again in mid January.

Very difficult to summarize everything since it depends on your weather (temps and snow), which chemicals you are using, what weeds you want controlled (only Poa or winter broadleafs or additionally summer weeds). So research and decide then comeback here an then I and others can give more specific advice.

To answer your primary question, if you use a PRE you should have very few Poa so with only 400 feet you can just pull those. If you want a POST atrazine works but very slow. Certainty works also, but in cooler weather it is slow.

 

I will try the Prodiamine for pre emergent then.
I would like to not harm the bare patches of ground I have. You mentioned possible trouble with bare areas.
I have 16X24 inch sod that I planted like plugs with 1 to 1.5 feet between them. No weeds there since I killed all weeds since last year and early this year. I hoe to remove any weed seeds sprouting.
I know this works well because my last years plugs of similar nature are growing long stolons, but have the weeds in them.
The new plugs are weed free and I will keep it that way with your advice.

The warm days are making the grass grow in overtime, so hoping the new grass will grow stolons soon.

 

If you have some areas you need filled in, just don’t put a PRE in that area. You may get a few weeds, but you can hand pull since it’s a very small area.

Get the lawn healthy and filled is the best weed prevention. Once you have that then you can use something like Indizaflam which will pretty much control just about every weed. It is a very strong root clubbing PRE so none in bare spots.