If you are considering growing vegetables in your garden (which I assume you are, based on where you posted this), I'd avoid Roundup as a way to prep your area. There are a couple recent threads (including one I started) about how to remove or kill grass for raised beds. If you're not going to be raising the beds, the conventional wisdom seems to be either rototill it (instant), or cover it with newspaper/cardboard to kill the grass (takes some time)

Ouch. Yes. There is some controversy about the timescale for biodegradation of glyphosate (Roundup). Monsanto would like you to believe that the half life in soil is a week or so, but even they admit that in some cases (and they don't really understand why), it lasts for months. That is, it's HALF GONE in months. If I were you, I wouldn't get Roundup anywhere near a garden (vegetables, flowers, shrubs, whatever) you're going to try to use this year. There's a procedure for you.

For most kinds of grasses, just tilling in will be adequate, and it'll do in situ composting in the bed. For Bermuda, it's uglier. Little pieces of Bermuda will each root and come back in spades. You can try to rip it out, and remove the roots, but you'll be weeding it for a long time.

Bermuda is literally my worst enemy of all time. with the way that it grows if I try to pull it up in one place I have to rip all down my bed before I can pull it up thus killing my plants. the only way that I've seen for getting rid of Bermuda is to dig it up and expose its roots to the hot summer sun and keep repeating this every few days-weeks to get it all out. IMO Monsanto is a bunch of cat piss. they have lied so much about their stuff and slowly more and more things against them are coming out. avoid roundup at all costs!

Dawson

It's not that hard to strip off sod, either by using a sharpened flat edged shovel, or by renting a sod stripper.

The OP is in zone 5 so I doubt that Bermuda grass is a problem.

but in zone 5 at least here in NH we have a problem with witch grass or quack grass that has long runner roots. I also have a problem with what I call Creeping Jenny. I would go with sod stripping if raised beds aren't being considered.

Urgh I fight Bermuda constantly. Dan, do you know if solarizing will kill it, WITHOUT having to till it up first? Half of what I've seen says to till, half says don't bother.

I'm on the hating bermuda grass train too. Never realized how horrible it is until I moved into my current house. Last summer I started 6 new raised beds by laying down cardboard on top of the grass and building the bed on top of that. I wouldn't doubt if I find bermuda grass surfacing in my raised beds later this summer or next year. That stuff never quits!

FORD:

Forget "Roundup" and get the generic 41% Glyphosate from WALMART. it's cheaper by a lot.

https://www.walmart.com/ip/Eliminator-Super-Concentrate-Weed-and-Grass-Killer-32-fl-oz/17126444

1. The grass has to be greening up, first.

2. Water it well, mow if you have a lot of dead stuff from the winter.

3. Give it a few days to get fresh growth and then spray the area with glyphosate, diluted and applied according to the instructions.

4. Let it die off and repeat steps 2 and 3 weekly until nothing comes back.

If you have something besides Bermuda grass, usually 2 applications a week apart will do it.

Sloan Quinn - The rhizomes can be deeper than the effects of solarizing can go. Luring it out with water, then killing it with glyphosate is the best method.

http://lazygardens.blogspot.com/2015/06/how-to-kill-bermuda-grass-in-10-easy.html

I think the point was that he/she should forget glyphosate, by whatever brand name. Unless you want to round up your veggies this year. But yes, glyphosate is terrific for killing grass (and lots of other stuff).

If the OP is wishing to make a bed in the lawn I doubt quack grass would be a problem. Unless it is a truly appalling 'lawn' ;-) If the lawn is reasonable I'd just dig the bed over inverting the turf into the bottom of the trenches as I went. removing the sod would remove a large amount of organic matter from the area. By incorporating it you get the benefit of the rotting material.

I am on board with everyone saying RoundUp is Evil, as even a breeze of it will cause tomato leaves to recoil in horror. Tomatoes are some of my favorite things to grow, so I never touch herbicides as they're incredibly sensitive.

And stripping away sod loses you a lot of good green organic matter, along with the best of the topsoil.

I thought this through early last spring, when I wanted to make a large garden on a sloping lawn/pasture type area. I hit on a good method; well, it worked, but it was extreme hard labor.

-First I laid heavy half-round timbers in the shape of long, narrow beds, by cutting little trenches into the sod and laying the timbers snugly into the trenches. I made some beds 4'x8' and some 4'x20'. (These timbers were salvaged from a friend who replaced his fences. I wanted to use heavy borders so that they could do a little bit of retaining, to mitigate the slope somewhat. I'm sure any border would work.)

-Then I used a freshly sharpened spade to cut a trench about 10" wide and 12"-18" deep across the short end of a bed, loading the soil onto a tarp and keeping the sod separate from the soil. Then I cut another, similar trench immediately in front of that one, turning each spadeful of soil carefully upside-down into the first trench, leaving the second trench empty and the first trench full, with the grass roots-up at the bottom. (I also worked in a little aged chicken manure while doing this.) And I worked my way down each bed that way.

-I put the sod from the first trench in the bottom of the last trench and filled with soil from the tarp.

-After doing ten long and eight short beds in this way, the grass between the beds was so torn up from foot traffic that all I needed to do was hoe it out, then cover the paths with wood chips.

-I started in February (from pasture) and planted in May. I still can't believe the sheer volume of produce I harvested. I miss it a lot. I'm in school now but I call home often to see what my family has planted in the garden I built.

-You already have a number of good answers, so I thought I'd contribute now as there's no risk of seeming as if to be saying this is the only way to go. I know there are lots of other good ways. But this is what I did, and it worked and is pretty, so I wanted to share.

It definitely is! I took a garden fork this year and dug down about 1 foot or so and flipped over the soil and broke in up to create about a 120 sq ft garden then I added some fertilizer as the soil was starved of nutrients and I also added a lot of organic matter, after all of this I waited a few weeks to wait for earthworms and such to appear before planting. I got a great cool season harvest and I'm now putting in warm season vegetables. it may be hard work for many of us lazy american's but it sure works and boy is it worth it.

Dawson

@Dawson I agree, break your back once and the bed will produce for a long time, I just keep adding leaves and compost and avoid ever stepping on it (no compaction), soil like a sponge. I do a quick break up with my garden fork just to loosen up the soil in the spring a bit unless there was a root crop previously in that bed, then it's all ready been broken up plenty.

@Steve - Instead of doing a quick break up with your garden fork there is a great tool out there called a broadfork that does the job better and is easier to use, plus you don't mix the soil levels so much. Here is a link to the tool: http://www.johnnyseeds.com/search/?q=broadfork

Yeah, I have been eye balling this one http://www.johnnyseeds.com/tools-supplies/johnnys-920-broadfork-9061.html#q=broadfork&srule=top-sellers&sz=18&start=1

Looks good for harvesting sweet potatoes as well.