1. Sprayed all the weeds with Round-up and killed 75% of the lawn right along with the weeds. (I know, I know!!)

2. Used a shovel and rake to remove dead weeds and grass and then went over it with a tiller.

3. Soil near the end of the lot is hard and using the shovel I could only break up a few inches at a time. Soil around the pine tree was even worse--rock hard.

I am willing to do the physical work required to bring this lawn up to par. It is tilled and barren now. Where do I go from here to re-sod with St. Augustine if I want to go the organic route?

Maybe this will help. Before you do anything else, spray your entire yard with 3 ounces of baby shampoo per 1,000 square feet. Measure the yard and pour enough baby shampoo into a hose end sprayer bottle. Spray the yard as evenly as possible until the soap is gone. USE BABY SHAMPOO and don't make the mistake of using anything else. Some liquid soaps have antibacterial agents in them. Baby shampoo does not. Get the cheap stuff at Wally's. Spray one time and follow that up with an inch of water (as measured with a cat food can). In a week give it another inch of water. In another week spray with shampoo again and another inch of water. The point of this exercise is to soften your soil deep down and possibly get that fluffy tilled stuff to settle down. Let it dry out enough so that it is solid enough to walk on. Look for low spots and level those with sand. Look for high spots and grind those off with the back of a rake or something. If you are entirely fed up with the uneven way it settled after the deep watering, post again asking about how to level it. The problem with your tilling it is the soil will continue to settle for 2-3 years. Once it finally settles it will be bumpy and uncomfortable to walk on.

After you have it sort of level and it's dry enough to walk on without sinking in, then lay the St Aug sod. Roll the sod down with a water fillable roller to get good contact with the roots above and the soil below. Roots will not grow through air. Water it only enough to keep the sod moist. That means about 10 minutes, 2-3 times per day. Do not saturate the soil again for a few weeks. At this point you want the sod moist and just the very surface of the soil underneath. Roots will knit in and you can start to back off on the frequency of watering. When you back off on frequency you have to water longer. Improper watering will kill your St Aug again if you are not careful. St Aug will change color and fold up when it it thirsty. If you see that, water right away. Otherwise it is good to let the surface of the soil become dry enough to be hard. With the soap in the soil it should be soft when it is wet and become hard as it dries out. That is normal.

Go to the Organic Gardening forum and find the FAQs. The last one is the Organic Lawn Care FAQ. Read that and come back with more questions.