Looks like Bahia Grass. If you have centipede sod, you can use Vantage to get rid of it. Be sure to read the label and have your mixture correct before you spray. http://www.amazon.com/Vantage-Grass-Killer-Herbicide-Pint/dp/B0053C9AYW

Yep. Whether Poa Annua or another bluegrass that is typical this time of year. It is having a banner year due to the longer winter and cool spring. It likes cool and damp and if it is the Poa Annua then heat kills it off. Don't water until you must and wait for the heat. A pre-emergent for crabgrass control in fall and early spring next season will knock it way back but those seeeds last years and nothing kills it that doesn't kill your turf as well. Also, next year if it starts popping up weeks before your lawn turn you can add vinegar to a pump sprayer and spray it and every 'early' weed before your grass greens up early in the day then the sun/acid will burn it right up before it spreads and goes to seed. What kind of (intentional) lawn do you have? Once the soil warms to around 70, especially if fairly dry and not shaded, this stuff dies out.

The purpose of the tilling was really to pull up some roots and get to what's underneath. The top is all hard and cracked. We got a ton of roots up and pulled out a lot of weeds. We'll be adding a bunch of new dirt and levelling. I've no doubt that will be a long process, but that's ok. This particular stretch does have full sun. It does have a small crepe myrtle, but that doesn't shade it much. This side faces the south, and being on the corner gets morning, afternoon and evening sun, only a tiny bit of it gets filtered by the crepe myrtle. My only worry is that it'll end up with a greenhouse effect and grow even better under the plastic..... That side has some bermuda already (and we left some areas. Plans for that stretch (which is actually bigger than I said - 37x17, I finally measured it today) are not settled yet. It'll have some bermuda in the center, but we're going to semi-xeriscape. I say 'semi' because we do want some grass, but we'd like to minimize water requirements. I'm going to put a border in around the perimeter, though I haven't decided which plants to put in. The border will be ~2 ft in (a little more around the wrap-around porch to incorporate some bushes already there. Along the fence line I'm still debating. We have an ugly chain link fence which we hate, but aren't planning to remove it any time soon. There's bermuda outside the fence in the front (no sidewalk there), but I was thinking of putting in some ivy-type ground covering (sorry, still learning all the names) which will creep over the ugly fence. On the inside we'll have the mulch with some drought-tolerant plants. There's an ivy-type plant growing elsewhere along the fence, but it's pretty messy and strangles the cedar elm, so I'm not sure I want to keep that. The whole property is 1/4 acre, so we have a fair amount of yard to deal with. As we're still in the midst of interior restorations, the outside is a slow process. It's mainly getting attention now because it's one of the few things I can do with my little one (compared to painting, sanding, hanging sheetrock....)

Round-up needs to be incorporated into the plant to do it's job, and it takes at least a few days for signs of plant death. I would wait as long as you possible can, watering your lawn so the weeds are actually growing, then mow and bag all the weeds as late as you can, and then use the power rake to get all the remnants before you lay the sod. Sod to soil contact is very important if you want your sod to root. I looked at that site, and I'm not sure what Soil Prep is, but I believe it's probably some sort of compost. I would probably omit this step as a two inch layer of compost will decompose which could cause some rooting issues. Sod needs to be laid on top of soil. Rolling the sod is a good idea.