Is seed or sod for better for new lawns?

Seeding a new lawn is economical and works well if done when the weather is right for seed germination. April and May or September and October, up to about October 15, are good months, when there's rainfall available and the soil and air temperatures allow seed germination. Other months of the year are far less successful for seeding lawns. Be sure to use seed adapted to western Washington conditions. Sod can be laid nearly any time, and provides an attractive "instant" lawn. The choice between seed and sod depends on how quickly it's necessary to get the lawn completed. Give sod the same good soil preparation as seeded lawns, be sure it makes firm contact with a prepared soil bed, and keep it irrigated through spells of low rainfall. Failure with lawn establishment results most often from improperly prepared soil underneath the lawn, which affects the lawn negatively whether seed or sod is used.  more