Will Frost Before Germinating Hurt Rye Grass Seed?
Ryegrass (Lolium spp.) is a cool-season grass that does very well along the coast where temperatures tend to be moderate. There are two types of ryegrass -- annual and perennial -- that are commonly planted, although perennial is planted more often. They can both be planted by seeding. Frost does not actually hurt the seed but it can keep the seed dormant until warmer conditions arrive.
Different Types of Ryegrass
When considering the pros and cons of ryegrass, consider that both annual and perennial types of ryegrass grow best in full sun, but perennial ryegrass will also grow in partial shade. Annual ryegrass (Lolium multiflorum) lives for only one year. It is still planted as a cool-season cover grass but it dies out each spring.
Perennial ryegrass (Lolium perenne) is often planted for lawns in U.S. Department of Agriculture plant hardiness zones 3 to 8, although it is considered invasive throughout much of the United States, according to the Invasive Plant Atlas of the United States. It is the most high-traffic tolerant cool-season grass species and is often planted in parks and around schools.
The University of California Guide to Healthy Lawns says that perennial rye grass germination happens so quickly that the grass fills in lawn areas fast, as long as it is planted properly and at the right time of year. It grows so quickly that other weeds don't have a chance to start growing.
Plant Annual Ryegrass Before Frost
The University of California Guide to Health Lawns reports that annual ryegrass should be planted in the fall. If it is planted too late in the fall, though, it may not grow. Plant annual ryegrass at least one month prior to the first expected frost. The frost and cool winter weather will not hurt the seeds but it can kill tender, young seedlings. This grass is not used for turf because it dies back in the late spring and early summer.
Instead, it is seeded for use as temporary soil stabilization, to provide some early spring color on bare ground or to overseed warm-season turf grass (overseeding is a term that means spreading seed over an existing lawn, explains the Clemson University Cooperative Extension). Homeowners overseed to provide fresh color while their turf grass is dormant, or to correct a thin patch.
Perennial Ryegrass Germination Time
Perennial ryegrass is planted in the fall and early spring. According to Nature's Seed, perennial ryegrass germination time is very short, at only five to 10 days, provided it is planted at the right temperature and they receive frequent but brief waterings to keep the soil lightly moist. After the seeds have germinated, begin watering more deeply and less often, to encourage deep root growth.
When planted in the fall, it should be planted one month before the first frost. In the spring, however, it is often seeded as soon as the snow melts. In fact, farmers often spread the seed in very early spring so that it will work its way into the soil naturally as it freezes and thaws. This is a process known as "frost seeding." When the grass grows high enough to warrant mowing, begin mowing the grass when it is 1/3 higher than the optimal height.
Preparing to Plant Ryegrass
Prepare the soil the previous fall when planting perennial ryegrass in the spring. When planting annual or perennial ryegrass in the fall, the soil can be prepared as late as one week prior to seeding. Whether the ryegrass seeds are planted in the fall or in the spring before the last frost, water the planted ryegrass seeds daily or as often as necessary to keep seeds moist until they germinate.
- University of California guide to Healthy Lawns: Perennial Ryegrass – Lolium Perenne
- Invasive Plant Atlas: Perennial Ryegrass
- University of California Guide to Healthy Lawns: Annual Ryegrass – Lolium Multiflorum
- Clemson University Cooperative Extension: Overseeding With Ryegrass
- Nature's Seed: How to Re Seed your Perennial Ryegrass Lawn