What little I know about prairie grass tells me that most of these native plants have really deep roots. Some up to 6 feet deep. Solarization of these grasses might take a very long time to completely kill the plant.

Here in Iowa many of the prairie grass refuges are managed each Spring with a controlled burn. Fire has historically been natures way of restoring these grasslands.

While some may prefer to cover an area with sheets of ugly plastic for weeks and weeks to solarize instead of burning...

A controlled burn could be done in an afternoon and you could be planting your grass seed in a few days. The fire will not kill the grasses but will take care of some weeds. It will also give you a clean palette to plant your seed.

Of course, local laws on burning and burning permits might not let you use fire to clear the weeds and grass on your property.

If you check with your county extension agent's office they will have details about using controlled burns in your jurisdiction.

If it was my yard, I'd burn it on Monday and plant my grass seed on Friday. (weather permitting)

Where in zone 8 are you? How large is the area you want to plant as buffalo grass?

Buffalo grass is a warm season grass that needs lots of sun to thrive. You should plant it in late spring when it's starting to get warm. Depending on rain patterns, you may have difficulty getting it to germinate well, since it will need water fairly regularly until it starts to grow. Once it gets established, you shouldn't have to water at all.

Sadly, I need to completely eradicate the prairie grass because it gets so tall I can hardly walk to my car or my compost pile without becoming covered in burrs and wondering what type of snake might be hiding below my knees. I know most people would say, just mow more often! But it grows SO fast we just can't keep up! And as far as space, we are talking about 2,000 sq feet for the area immediately around the house and when I do the back yard that will be about 5,000 Sq feet. I can procrastinate on the back yard until next year but I would like to get the front yard done this year (so I can get to the car, etc). I'll be leaving a large part of the yard still wild.
I am in Central Texas hill country. Very alkaline soil with shallow limestone shelf. If I am planting anything larger than a gallon pot (and sometimes less) then I need a pickaxe. Watering by hose/ irrigation may not be possible due to watering restrictions so I am hoping to take advantage of the spring rains. Sometimes we go months without a drop of rain.
If I have to use herbicides I guess I will. :( I definately need to kill the tall grasses or they will shade and choke my Buffalo. I'd rather not have to do that, though.
Oh, hungry deer are a big problem out here too.
Who knew it was so difficult to be environmentally friendly?
Thanks for your replies!

You're probably right thinking that you'll need to kill the existing grass to give the buffalo grass a chance to establish. I'm not sure if solarizing will work or not, since that's such a large area.

I'm not familiar with the rain in your area, but if you get spring rains when the soil is fairly warm, you may be able to get the buffalo grass to sprout with the spring rains. You may even try seeding before it's warm enough for the grass to sprout (dormant seeding, but later than dormant seeding a cool season grass).

Unfortunately, I think that trying to take advantage of spring rains may preclude using solarization to kill the existing grass, since you'll need sun and heat for the solarization to work.

Buffalo grass should do ok in alkaline soil. The hungry deer will probably appreciate the buffalo grass, but I'm not sure that's going to make you happy.

If you can get it established, you can probably let it go without mowing, since it will probably only grow to about 4 inches high.

As a side note, buffalo grass is often planted in mixtures with blue grama. But blue grama will grow taller, so if you want it to look like a lawn but don't want to mow, that might not be your best bet.

If you are talking about Johnson grass (or any other bunch grass or tap rooted grass/weed), you might be able to control it with a Weed Hound tool. You can get one just about anywhere for $20.

Buffalo grass is well known for being weedy, so I'm not sure you're going to get what you want with this plan.

I've been watching these forums for years and have never read anyone having good results with solarizing. It might work in the heat and sun of summer. You can smother almost any grass with a couple inches of sand and fine mulch. I killed about 400 square feet of bermuda last summer with sand and mulch. Key to that approach is that no green part of the underlying grass/weeds can ever see any light. Any sprigs must be removed as soon as you see them.

you might want to check out Green Gaurdian's everything must go. It's basically an organic round up. It seems that that will be your only true way of killing the grass and weeds you want to get rid of. Check out their website...

http://www.greenguardian.us/prod_weedcont.html

I haven't used it but it seems to be pretty good.