Crop and Soil Environmental News, March 2008
Author: Mike Goatley, Jr., Extension Turfgrass Specialist, Virginia Tech
After selecting the best lawn grass for your site, there are several important steps to follow to optimize your chances for success whether you are establishing the turf by seed or sod.
Choose certified seed. Look for the “blue tag” that indicates the seed is certified. This is your guarantee that what is on the tag is actually in the bag. The seed tag tells you individual cultivars and their percentage by weight that is in the bag, and also tells you their germination percentage. Shop for seed that is as “weed free” as possible (also listed on the tag) and purchase seed that was tested within the past calendar year. Several of Virginia’s sod producers also participate in certification programs as well and where available, this further assures you of your purchase of high quality, pest-free sod.
Use appropriate seeding rates. Each grass species has a recommended seeding rate to optimize establishment potential. In units of pounds/1000 sq ft, the seeding rates are as follows: Kentucky bluegrass or zoysiagrass, 2-3 lbs; tall fescue, fine-leaf fescue, perennial ryegrass, 6-8 lbs; bermudagrass, 0.5 to 1 lb, and centipedegrass, 0.25 to 0.5 lb. Follow the recommendations on the bag for appropriate seeding rates for mixtures of different grasses. For all cool-season grasses, use the higher seeding levels listed for spring plantings.
Soil to seed/sod contact is a must. As a seed germinates, its root system must quickly establish contact with the soil to ensure the new plant has ready access to water and nutrients. New establishments into a tilled, smoothed, soil that has been fertilized and limed according to soil test recommendations have the best chance for success for either seed or sod. Starter fertilizers that emphasize phosphorus (e.g. 5-10-5) are often used irrespective of a soil test results and they typically prove beneficial for early root development. However, be reasonable in their use because misapplied phosphorus is one of our biggest concerns for water pollution potential.
Avoid a common mistake in soil tillage for a lawn: pulverizing the soil. Till the soil thoroughly, but don’t attempt to destroy every clod (even for sod installations). A soil being prepared for a lawn should never be worked into a powder. Spot renovations of existing lawns also require some degree of soil preparation to succeed rather than just sprinkling seed on the ground. There is a special name for seed sprinkled on the ground –bird food! Work the soil surface with a heavy garden rake or other hand-held garden/plant bed weeding tools, or use power equipment such as a coring machine or a vertical mower to prep an existing lawn site prior to seeding. If you really want to impress the neighbors, rent a power seeder that preps and seeds in one operation! Give some attention to seed planting depths when using power seeders. Small seeded grasses like Kentucky bluegrass, bermudagrass, and centipedegrass need to stay right at the soil surface while the larger seeded grasses like fescues and ryegrasses can be planted as deep as 0.5 inch. Finally, it is best to seed in at least 2 directions whenever possible to ensure you don’t have skips in coverage.
Post planting care. Appropriate water management is the key to success and is especially critical for the first summer survival of cool-season grasses. Sod is very forgiving in moisture management because the soil serves as a water reservoir. Simply keep it from drying out. Keep seed establishments moist but not saturated by following a “light and frequent” irrigation strategy. Commercially available mulches or seed germination cloths can assist you in conserving moisture, but quality, weed-free wheat straw (1 bale/1000 sq ft of area) works great too (and can simply be mowed back into the lawn later). After germination is complete, the irrigation strategy for an establishing turf should slowly return to a “deep and infrequent” approach. When should you mow the turf? When it needs it! Keep the “1/3rd” rule in place for any grass, meaning that you should never remove more than 1/3rd of the leaf blade in any mowing event. Regular mowing during the latter stages of establishment will actually encourage lateral growth and finer leaf blades that will improve both the density and appearance of the lawn. Feed the new turf periodically for the remainder of the spring, but alter your approach depending on whether or not you have planted a cool-season or warm-season grass. Cool-season turfs will respond favorably to responsible nitrogen (N) fertility during establishment. Consider one to two applications of water soluble N sources delivering up to 0.5 lb/1000 sq ft on a three to four week interval through the month of May, or use an organic fertilizer and apply 1 lb of N/1000 sq ft in a single application to carry you the through spring and into the summer. If you are establishing a warm-season grass, then you can be more aggressive with your N fertility program since the summer is the ideal growing period. Lastly, expect some weed pressure and if you need to treat, use caution. Follow labels carefully to avoid damaging your new turf and consider utilizing the expertise of lawn care professionals to select and apply products that can maximize weed control without damaging your investment in a new lawn.
Looking for more information? Your local Virginia Cooperative Extension office has plenty of information specific to your location on many lawn and landscape topics. You also have a wealth of information on best management practices in lawn care available at any time by logging on to www.ext.vt.edu/.
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