Lawn construction and renovation
By Dawn Pettinelli - UConn Home & Garden Education Center
Feature Article - posted Tue., Sep. 6, 2011
The cooler weather of September is the perfect time to establish new lawns or renovate those that have deteriorated. In general, renovation is recommended for lawns having 50 percent or more bare spots or weed species. Smaller areas usually do not require extensive renovation and may just need to be reseeded.
When constructing a new lawn, a little extra effort in site preparation will reward you with healthier, greener, lower-maintenance turf. Good drainage is essential. Typical cool season turf grass species will not do well on poorly-drained sites. Either the drainage situation will have to be improved, or consider using this type of area for a rain garden, raised planting beds, or maybe even installing a water feature.
Turf grasses also require at least 6 to 8 hours of direct sun each day and 5 to 7 inches of topsoil in order to thrive. Most of Connecticut is covered with sandy loams which are an ideal texture for growing turf. When mixed with a little water, sandy loam soil will have a slightly gritty feel to it. If your soil is either too sandy or too clay-like, additions of organic matter will improve the soil’s structure, as well as the water-holding capacity, drainage and other physical properties.
The ideal soil pH for turf is around 6.4, so limestone applications may also be needed. Soil testing will recommend how much limestone and also fertilizer to apply before seeding. Visit www.soiltest.uconn.edu for information on soil testing. Without a test, use a starter fertilizer as recommended on the package and about 50 pounds of limestone per 1,000 square feet. Rototilling the organic matter, limestone and fertilizer to a depth of 4 to 5 inches will distribute the amendments evenly.
Prepare the final seedbed by doing any necessary grading. A lawn roller is useful to flatten the area after rototilling. Lightly go over the area with a rake following rolling to loosen the soil surface before seeding. Without a lawn roller, just use a grading rake.
Lawns to be renovated require weed control and soil cultivation before seeding. Limestone and fertilizer can be applied as recommended by the package or a soil test. Broadleaf weeds can be dug out by hand or controlled selectively using herbicides for broadleaf weeds in turf. Areas with perennial grassy weeds such as quackgrass can be dug up or sprayed with a non-selective herbicide, which will kill all the vegetation at that site. Lawns are generally mowed very low before overseeding.
Thatch accumulations of more than one half inch should be removed using a rake in small areas, or using a dethatching machine called a verticutting or power slicing machine for large areas. This machine slices quarter-inch grooves in the soil while removing the thatch layer. It exposes the soil so the seeds have a better chance of making contact with it and germinating. A core aerator can be used on compacted soils. It pulls up plugs of soil, allowing water and air to penetrate the grass root zone.
Now is a great time to seed. A mixture of turf grass species is typically recommended because, as a rule, mixtures are less susceptible to disease and insect problems than single species. Most cool season turf grass mixtures contain Kentucky bluegrass, fescues and perennial ryegrass. For either a lower-maintenance lawn or for partially-shaded sites (four hours of direct sun each day), think fescues. Either the turf type tall fescues or the finer leaf fescues require less water and fertilizer and tolerate more shade and lower pH levels than Kentucky bluegrass does. Check out www.turf.uconn.edu for more information on fescues.
Approximately 4 pounds of seed per 1,000 square feet will result in good coverage. Spread one half of the seed in one direction over the entire area with a drop spreader and the second half in the perpendicular direction. This will prevent bare spots. Go over the newly-seeded area lightly with a rake, taking care not to bury the seeds, but just ensure good contact with the mineral soil.
Moisture is critical for turf grass establishment. Frequent, light sprinkling is recommended until the seeds germinate. That may take seven to 21 days, depending on the grass species. A light covering of mulch hay is used by some to aid in moisture retention. When the new lawn has reached about 3 inches in height, mow it to 2 inches. Additional fertilization will not be required until next spring.
While it takes a little more work to properly install or renovate a lawn, the long-term results are worth it. If you have questions about lawn care, construction or renovation, or on any other home and garden topic, call the UConn Home & Garden Education Center (toll-free) at 877-486-6271, visit www.ladybug.uconn.edu, or get in touch with your local Cooperative Extension Center.