Fertilizing New Sod
Most new sod is well rooted in 7 to 10 days, but avoid walking on the newly sodded lawn for at least 3 weeks--a month is better. If tender new roots are stressed while they are growing into the soil they will take longer to establish the new turf.
A month after it is laid, the new sod might appreciate a snack. Spray it with a liquid lawn fertilizer with a hose end sprayer. Do not use a fertilizer/pesticide combination. Follow the instructions on the package carefully. This snack, combined with the slow acting granular lawn fertilizer mixed into the soil prior to laying the sod, provides all the nutrition the new lawn needs for root and shoot growth until the next regular spring or fall feeding.
Mowing New Sod
Wait as long as possible before mowing your newly sodded lawn for the first time. Mowing requires walking on the turf which can harm the new roots connecting it to the soil. It is a good idea to let the grass grow at least 3 inches tall; 4 is better. If you are sodding some of the southern grasses you will need to cut the new turf a bit sooner.
For that first mowing take just a little off the top and come back 2 or 3 days later and take it down to two inches. Taking the time to cut the grass a little bit twice is less stressful on the new turf that coming on with one deep cut.