Purchasing Grass Seeds

There are two ways to purchase grass seed. You can visit the garden section of a retail store and pick out a package labeled with intended use, such as "Shade Mix." Or you can buy the latest cultivars and make up your own mix. For this you will need to nose around, starting with a good nursery. If the nursery doesn't carry what you want staff there can probably suggest where to shop. Calling the customer service departments of the large seed producers should also yield results. Either way, you will still need to know the basics about purchasing seed, beginning with the terms species and cultivar.

The word species refers to a group of closely related plants that differ from one another in only minor ways. Tall fescues are one species of lawn grass. The various members of a species are called varieties (which originally occurred in nature) or cultivars (variations that came about in cutivation, as a result of deliberate breeding). In common usage the terms variety and cultivar are often interchanged, but there is a difference between them. Grass cultivars include old standbys, such as the tall fescues 'Alta' or 'Kentucky 31', as well as new types that have been bred and chosen for superior characteristics. Newer grass cultivars, in most cases, are highly recommended.

Understanding Grass Seed Labels

The grasses being bred today have numerous advantages over their older cousins. For starters, many display increased insect and disease resistance and improved drought tolerance. To reap the benefits such grasses can provide, you'll need to introduce them into your lawn through spot reseeding, lawn renovation, and planting anew. Read the grass-seed label to see whether disease-and pest-resistant cultivars are in a given box of seed.

Blade type. Fine, narrow-leaved grasses produce attractive and more uniform lawns. Coarse grasses are better for areas that receive hard wear.

Kinds and percentages (purity). Package labels must state the name of each kind of seed present and its percentage in the mix. In high-quality seed mixtures, 80 to 100 percent of the total mix will consist of desirable permanent lawn species. The published percentages are based on weight, not the number of seeds. For example, there are approximately 500,000 fine fescue seeds per pound of grass seed and 1 million bluegrass seeds per pound. Thus, in a 50/50 bluegrass/fine fescue mixture measured by weight only one-third of the total number of seeds is fine fescue, and the blue-grass would predominate with two-thirds of the seeds. (This is desirable because, given their vigorous nature, the fine fescue seedlings would otherwise overwhelm the bluegrass.)

Cultivar. The trade names of the varieties included in the mix and not just the generic names, such as fine fescue, should be noted on the label. When they aren't, an older variety that may not have the advantages of the improved species has probably been used. Germination. This is the percentage of seeds expected to produce plants under favorable conditions. Look for a minimum germination rate of 75 percent for Kentucky bluegrass and 85 percent for perennial ryegrass, tall fescue, and fine fescue.

Test date. This is the date seeds were tested for germination rates. Most states consider germination percentages to be reliable for up to nine months after testing. As the seed ages, the germination rate decreases.

Weed seeds. Good-quality grass seed usually contains no more than 0.5 percent weed seeds; high-quality grass seed has none.

Noxious weeds. These are troublesome plant species that are difficult to control. Each state has its own list and amount per pound allowed. Avoid any if possible. Check with your Cooperative Extension Service for an up-to-date list of these noxious weeds for your area before purchasing seed.

Inert matter. This is dirt, chaff, and other bits that take up productive seed space. Inert matter should be no more than 5 percent. The less, the better.