Clear out any debris in the planting area. This includes weeds, rocks and old roots. It is most important to rid the area of weeds, as bahia grass seedlings cannot compete with other vegetation for moisture and soil nutrients. If you have a large weed infestation, you may need to apply several herbicide applications. After clearing the debris and adding soil amendments, all that needs to be done is the installation of an irrigation system and a final grade --- at a 2-percent slope away from the house.
Obtain a soil test from your county agricultural extension office. The tests are inexpensive --- free in some counties --- and the information gleaned is invaluable. The extension agent will work with you to determine which amendments to add to the soil to ensure that your bahia grass lawn gets off to a healthy start. Some common amendments include lime, phosphorous and nitrogen. You may need to amend the soil with sand or compost to rid it of drainage problems as well. Three to 6 cubic yards of organic amendments per 1,000 square feet of lawn area are generally sufficient, according to turfgrass specialists with the University of Florida. Note that some states, such as Florida, mandate a limit on the amount of nitrogen homeowners are allowed to apply to the soil.
As a general rule of thumb, 5 to 10 lbs. of bahia grass seed per 1,000 square feet of soil will provide a lush, dense lawn. The recommended rate for pastures is 10 to 25 lbs. per acre. Spread bahia grass seed by hand on small areas, and use a broadcast spreader for larger lawns. Avoid the temptation to spread more than the recommended seed amount. Too much seed causes competition among the seeds and irregular germination. After spreading the seeds, run a rake over the area to lightly cover the seeds with soil.
The most important aspect of bahia grass germination is irrigation. Immediately after you've planted the seeds, they should be watered with a light mist to prevent them from washing away. If there is no rain forecast, water the seeds often enough to keep them from drying out. During hot periods, you may have to water several times a day. Keep pets and people off the area until the bahia grass is established.