Not only will freezing grass seed not kill or damage the seeds, if done properly and in a controlled environment, freezing the seeds can allow for faster germination in the seeds. Freezing can actually be an effective way to store your grass seeds prior to use.
Damage from Freezing
Contrary to popular belief, a frost or full-on freeze will not harm your grass seeds. While grass won't typically grow during a freeze, which is why you shouldn't plant your grass seed until outdoor freezing is expected to be over, the seeds will still produce grass after a freeze.
Benefits of Freezing
Freezing your grass seeds allows them to germinate much faster than normal grass seeds. The germination process is when the plant emerges from the seed. Faster germination means that your seeds will take root and grow in a quicker manner, resulting in less erosion and top soil loss.
Freezing Seeds for Storage
Grass seed can actually be frozen for storage, which will ensure that the seeds are ready for rapid germination when planted. Seeds should be placed in a sealed bag to prevent spillage and contamination from other frozen goods in your freezer.