Plant sod during the active growing season for the species you are installing. Cool-season grasses grow well when they are planted in the early fall or early spring. Warm-season sod should be installed in mid to late spring.
Plant sod when it is cool and humid outside for best results. Make sure it is laid down at least 30 days before the first frost, so the roots have time to strengthen before winter. Moisture is important to the overall health of the sod. That's also why it's important to lay it down as soon as it arrives, so it doesn't dry out.
Give new sod water daily for six weeks. Water to a depth of 6 to 8 inches, inserting your finger into the soil to determine when more water is needed. Hold off on mowing the grass until the roots have grown into the ground below.