After you carefully prepare soil for grass seed and then broadcast the seeds evenly over your turf area, you must protect these seeds while they germinate. Applying a thin layer of mulch over grass seed helps conserve soil moisture, which will enable the seeds to germinate more successfully. Straw and hay frequently serve as mulch for grass seeds because these materials are inexpensive, and they work well to keep the seeds adequately moist. Apply the mulch at the proper depth to ensure the grass will germinate and grow through the mulch.
Pull handfuls of straw or hay from the bale(s) to apply the mulch over the grass seeds. You will need one bale of straw or hay for each 1,000 square feet of seeded lawn. Strive to cover one-half to three-quarters of the ground with mulch (keeping one-half to one-quarter of the ground still visible through the mulch).
Continue applying the mulch to spread the straw or hay evenly.
Water the grass seeds through the mulch to keep the soil evenly moist.
Rake up the hay or straw after the grass seed germinates, or leave it on the soil. If you leave the straw on the soil, mowing will break it up into small pieces that will be undetectable within the grass as the grass fills in the turf.