Over-seeding with winter grass (also known as rye grass) is a great way to keep your lawn beautiful throughout the winter months. The local temperature range normally dictates that winter rye seed can be spread in early to late October. It is important to know, however, that rye grass has some disadvantages. For example, the rye grass can compete with the St. Augustine grass for space and nutrition, which makes it difficult on the St. Augustine in the spring. This struggle is particularly apparent in shaded area where grass already has a hard time growing.