Some gardeners labor under the myth that laying sod gives them an instant lawn. In a real sense it does, but just as much soil preparation is needed to improve the ground in July as needed for the grass seed planted in September. For that reason it's sometimes best to lay sod in small sections, rather than all at once.
If you do this, store any extra sod on plastic, in a semi-shaded place. Keep moist.
To prepare the ground for laying sod, spread 2 or 3 inches of peat moss, a dusting of ground lime, and a special high-nitrogen lawn fertilizer over the soil. Then dig all of this into the top 6-inches of soil, so everything is thoroughly mixed, now firm the soil with a roller, or with your feet in small areas. This firming gives the grass roots a solid surface that will not sink later on.
Note here: Be sure fertilizer is thoroughly mixed with the soil to prevent root burn. Take care to read the correct application and amount of fertilizer to add to the area.
Once you have the soil firm, use a rake and level the surface.
Now for the sod itself. This may not be instant gratification, but it is a quick and painless way to get a handsome lawn. There are no weeds, and it produces a lawn in an afternoon that would take about 2 years if started from seed. The thickness of the roots should prevent washouts and erosion. When all the time and labor are figured, the cost will most probably be worth it.
Sod is grown in special sod nurseries and is prepared for sale by a cutting machine that slices through the soil about an 1 to 2 inches below the grass. Then this 1-inch or 2-inch thick strip of sod is rolled up jelly roll style, which is the way it is sold in most garden centers. The only thing left for you to do is unroll the sod like a carpet. While you are doing this, lay boards over the newly laid sod and stand on the boards, not on the firmed soil, because footprints will leave the surface of the soil uneven.
Within about 2 to 3 days the grass roots should begin to grow into the new soil, and after a few weeks, with a little moisture, there will be a firm lawn to be proud of.
Note: Thanks to my husband for helping me with this.