Ask Mr. Smarty Plants

Native grasses and flowers need light to germinate.  They will do best if you remove your grass, then water the ground well and let whatever wants to sprout, sprout.  Then lightly hoe – right at the ground line or till VERY lightly (1"), so you don’t bring more dormant seeds to the surface. You may need little or no compost.  Work it in lightly so the seeds won’t be in straight compost. Rake very lightly after seeding. You should still be able to see some seeds. Do not add mulch.  It will block the light and hold too much water around the plants.

Native American Seed has an article on how to prepare your soil. If you can do it, they suggest setting your lawn mower so low that it will scrape the soil.  I cleared a little bed for just wildflowers in the midst of a grassy field by using a string trimmer the same way.  I ended with bare soil and then raked it, added the seeds, lightly raked, and lightly watered in.  I also keep the area moist between rains until the flowers had sprouted. But getting the area completely clear of vegetation is key to success

Aggie Horticulture has an excellent article with pictures on how to prepare your soil. I’m not sure what kind of soil you have, but suspect it is clay.  Instead of compost, or in addition to very little compost, you might want to add decomposed granite (which is recommended for the Central Texas clay soils) or consult a nursery on a soil  amendment to make your soil drain better.  But if you already know your soil is draining well, you may only need to prepare the soil and add no amendments. Wildflowers and grasses  are designed to grow in fairly dry places in bright sun.

And one little tip not covered by your question. Mix your seed with damp soil and then broadcast it to get a more even coverage.  Lightly rake the seeds in. Some seed should still be visible. Water the seeds in very carefully so you don't wash the seeds out of some locations and pile them up in other places. Water whenever the soil is dry  between rains. 

I’m not sure if you plan to plant a meadow or a wildflower garden. A meadow is a mix of grasses and wildflowers. Having grass as part of your mix will help keep the weeds from sprouting in your garden and give wonderful movement. But  you only need  to change your mix to one of both grasses and flowers to get the prairie.  Preparation of the soil is the same.  Nativie American Seed has a seed mix for a pocket prairie.

If you are interested in learning more about growing prairies, you might visit the Native Prairies of Texas Association’s web page.  In the section “Manage”, you will find information on preparing and maintaining a little prairie.

For further reading you may like to check out the following:

Making a Prairie Garden. This is information for Ohio but the preparation would be the same.

Designing and Planting Your Native Garden by Neil Diboll

 Native Texas Plants: Landscaping Region by Region by Sally and Andy Wasowski.  I don’t currently have access to this book but think she has a chapter on gardening with Native Grasses. Your local library should have it or be able to get it for you.

Prairie-Style Gardens: Capturing the Essence of the American Prairie Wherever You Live by Lynn Steiner. This is a new book but the review I read made me want to own it.