sod. Additionally, since the sod is not grown in soil, it does not need to be washed clean of soil down to the bare roots (or sprigs), so time to export is shortened. Immediacy In many applications, such as erosion control and athletic fields, immediacy is a key factor. Seed may be blown about by the wind, eaten by birds, or fail because of drought. It takes some weeks to form a visually appealing lawn and further time before it is robust enough for use. Sod largely avoids these problems, and with proper care, newly laid sod is usually fully functional within 30 days of installation and its root system is comparable to that of a seeding lawn two to three years older. Sod also reduces erosion by stabilizing the soil. Many prized cultivars (such as Bella Bluegrass, a brand-named dwarf variant of Kentucky Bluegrass) can only be reproduced vegetatively rather than sexually (via seed). For these, sod cultivation is the only means of producing additional plants. To grow these varieties for sale, turf farms use a technique called sprigging, where recently harvested sod mats are cut into slender rows and replanted in the field. Cultivars used Fescue grass Tall fescue Tall fescue (Festuca spp.) is a cool-weather group of grasses originating in Europe, commonly used as sod. It is moderately tolerant to both drought and cold, and as such is especially popular in inland temperate environments referred to in the turf and landscaping industries as the "transition zone", where summers are too hot for most cool-weather grasses, yet winters are too cold for most warm-weather grasses. Fescue is well-adapted to clay soils, moderately shade-tolerant, and somewhat resistant to disease, yet vulnerable to the diseases brown patch and Fusarium patch. It grows most actively (and thus provides the most desirable appearance) in spring and fall, and requires frequent watering during summer. Due to its bunch-type growth habit (unique among common sod grasses), it will not spread undesirably or invade adjacent areas once sodded, yet neither will it fill in voids, and periodic maintenance (such as overseeding with Fescue seed) may be required to sustain a homogeneous surface. It has poor wear tolerance compared to Bermuda grass, making it less popular for applications such as athletic fields. Fine fescues Fine fescues (F. rubra, F. ovina, F. trichophylla) are less popular as sod than the tall fescues. As their names suggest, they