Lawn seed blends are a combination of two or more cultivars of the same grass species. The selected cultivars each add different strengths, which help the lawn withstand stresses such as changes in light, temperature, foot traffic and water conditions. The best lawn seed blend depends on your growing conditions, with different blends better suited to shade, full sun or hot Southern climates.
For Full Sun: Kentucky Bluegrass Blend
Kentucky bluegrass (Poa pratensis L.) spreads by rhizomes under the soil to form a dense, fine-textured lawn in sunny northern and mid-Atlantic growing areas. According to the Ohio State University Extension, Kentucky bluegrass is winter-hardy and drought-tolerant. A blend of several Kentucky bluegrass cultivars will include some that are more shade tolerant than others, allowing for uniform lawn growth throughout the differing light conditions in a typical yard.
Kentucky bluegrass can be slow to get established, however, so the Cornell University Cooperative Extension recommends seeding a Kentucky bluegrass blend in a mixture with a small amount of perennial ryegrass, which establishes much more quickly. However, don't purchase a lawn seed mixture with more than 20% ryegrass seed, as its swift, efficient growth will deter other more desirable grass varieties from sprouting.
For Shade: Fine Fescue Blend
The University of Illinois Cooperative Extension recommends a blend of fine fescue (Festuca spp.) varieties for shade lawn planting. Fine fescue cultivars--like Red, Hard, and Chewings fescues--all have forest-green color and fine-textured blades, which create an elegant appearance. Fescue has lower sun requirements than Kentucky bluegrass, and will grow in dappled or intermittent shade.
However, Cornell University Extension points out that fine fescue does not stand up well to heavy traffic. Create walkways in fine fescue lawns with stepping stones, pavers, or woodchips. Sow in a mix of a Kentucky bluegrass and fine fescue blends in areas which receive mixed sun and shade through the day or as the seasons change.
For Southern and Mountain Lawns: Bermudagrass Blends
Bermudagrass (Cynodon spp.) is drought and heat tolerant, with fine, dark green leaves. According to the University of Missouri Extension, some Bermudagrass cultivars are also cold-tolerant. A blend of Bermudagrass varieties will ensure that the lawn recovers quickly from any occasional cold snaps or periods of excessive rain. Specific commercial blends are available tailored towards colder, transition-area climates, as well as for short-mowing applications like golf courses.