Kill grass with glyphosate or slice with spade or sod cutter (if you can find one for rent) and roll up, cart off (laid upside down can fill a low spot). After you are sure all grass is gone till in amendments if you think the soil needs additional organic matter (it may not), rake it out and plant. Mulch after planting.

Sample soil and have it analyzed to check fertility.

This will be more work to maintain than a shrubbery. Expect to be weeding, deadheading, staking and dividing - unless you plan carefully to avoid kinds that require the last three chores (you are not likely to avoid the first with herbaceous plants unless you use only kinds that make a thick, blanketing growth).

Suzanne,
Do check out lasagna gardening before doing anything that's too strenuous or requires chemicals. It's the easiest way to make new beds and improves the soil, too.

You'll find lots more about it here at the forums, and by doing a Google search.

Here is a link that might be useful: lasagna gardening

Suzanne, your fall timing is perfect. I'll echo treelover's suggestion as I've done this many many times. Layer cardboard then browns and greens directly over the grass. You want a nice thick layer if possible as it will settle over the winter. I've added wood shavings as well when I've had them. Add compost if you have some under the cardboard to 'start' the process. By spring, you can plant in this. No chemicals, and a good start to your bed.

On occasion when I've not had a deep enough layer, I've had to go in and remove the occasional bits of sod (turned them over). But it is still less work than removing the sod, or using Roundup.

Not to hijack your thread, but I'm in need of the same advice. Come spring, I will need to have prepared beds ready to plant (Daylily seedlings). If I followed 'plantfiend's' suggestion, how high does the raised bed have to be? I'm thinking about doing as you suggested, but I probably won't have enough material to make the bed very high now. Hopefully will have enough to kill the weeds there (don't want to dig - too much rocks and what will now be petrified tree roots/branches). In the spring, how about if I build a wall around it (8ft long wood ties) and then fill it with triple mix? Would 12" high be enough? Ideally would love flat rock to make beds, but, you know (lack of $).

Plantfield and Treelover, I have lots of manure (from my horses) does it have to be completely composted to use them in the layered bed? I have lots that's been sitting for 8 months now. Plus I imagine I can add layers all winter if the snow wasn't too deep?

I am getting excited about this layered gardening technique!

mitanoff: Where my existing soil is okay, I sometimes just use cardboard to kill the grass, coffee grounds to attract earthworms & any lawn clippings and/or leaves I might have on hand, before covering it all with mulch (optional) and waiting for the grass to die. With enough moisture & time, the cardboard will decompose and then you can dig & plant.

If your soil is poor or rocky, the higher you build your lasagna layers the better, allowing you to plant without having to dig into the original soil. Twelve inches could easily compress to only a couple of inches by spring.

This time of year you should be able to find lots of leaves to use as browns. Alfalfa pellets from a feed store can be used as a green, if you don't have access to other greens.

I'm not familiar with triple mix, so can't comment on that.

Suzanne: If you aren't going to plant anything immediately (Some lasagna gardeners do), using your slightly aged manure should be okay. I would think you could continue adding stuff as you want, keeping in mind that it does take time for things to breakdown.

This is a very forgiving process. As long as everything you use is compostable, it will break down given enough time.

One caution about using your horse manure - do you use hay in the stalls? If so, the hay seed will germinate in your garden and make for lots of weeding. Unfortunately I know from experience.
One of my friends switched from hay to sawdust and that solved the problem for her. I think they say 6 months to compost the manure.

drtygrl, fortunately, I use pine shavings in my stalls. There is a little hay here and there but not very much.

I wonder if I should put black plastic over it in the early spring or maybe all winter? Isn't that supposed to kill seeds/weeds too?

You don't need plastic. If you take a newspaper, it works quite well. And earthworms LOVE newspaper. If you don't...corrugated cardboard is good too. You can usually find a store that will let you have as much as you want...most landfills won't accept it, and they have to recycle it.

bboy is right about the weeding, deadheading,etc...but I find if I spend 15-20 min/day every day it never gets too onerous.

A few years ago, when I was making lots of new beds, I used newspaper (about 5 layers) and cardboard (one layer) in different places. Refrigerator boxes, $2 each at my local appliance store, were great because they didn't require a lot of piecing. I did find that with rain and/or watering, the cardboard disintegrated faster than the newspaper.

I also noticed that Bermuda grass will grow through or around both those materials . . . though I doubt you have that in NH.

It's been very dry where I am and, two years later, I'm still finding both materials intact in locations where I'm just now getting around to planting things---areas that I haven't been watering.

What I have access to alot of is newspaper. I know that I should not use the glossy stuff but what about the colored in on the regular news print? My local papers have colored sections within the paper.

I used newspaper with black and white and colors (comics). It breaks down pretty good in one winter, but better after a couple. I love lasagna gardening. If you are stingy on the newspaper sheets, some grass will grow through. But its not too hard to pull it up the next year.

I've read in some places that the colored inks used on newsprint (not the shiny paper) is generally soy based these days, so okay to use. Other sources state that there are still heavy metals in some colored inks.

If you're concerned, you might want to contact the printing company that produced the newspapers you're planning to use.