Renovation describes corrective procedures to restore beauty to an old lawn without removing all of the sod. It can be as simple as overseeding a thin turf area or can include power raking and core aeration if thatch is greater than 1/2 inch or the soil is compacted. It is a much more severe treatment than normal dethatching (power raking), which should be practiced on lawns as needed. A total renovation would involve killing the undesirable grasses with a nonselective herbicide and may require more than one spray application (see Item 7 on back). Ninety percent of turfgrass renovations are not successful as far as changing turfgrass species due to the fact the areas are usually sprayed once, overseeded, and expected to be totally converted to a new species. When not done properly, the site will look good to begin with, but will eventually return to the conditions (species) existing before renovation. If all sod is removed and soil cultivated, follow procedures for establishing new lawns.
Some management practices will cause turf problems to develop that require renovation to correct. These problems and a brief description are discussed.GRASS SELECTION
Kentucky bluegrasses, fine-leaved and turf-type tall fescues are
best adapted for eastern Washington. Turf-type perennial ryegrasses, fine-leaved fescues, and bentgrasses are well-adapted to western Washington, with more evaluation of tall fescues being conducted. Kentucky bluegrasses are usually shortlived in western Washington and only selected improved cultivars should be used and never seeded alone.
Homeowners who prefer bentgrass lawns in western Washington should plant only the colonial types such as Bardot, Tracenta, Highland, Astoria, or Exeter. Never plant creeping bentgrasses such as Seaside, Penncross, Pennlinks, Putter, or Emerald. These varieties have vigorous growth habits and excessive thatch forming characteristics for home lawns. The average homeowner does not have the equipment and, frequently, the knowledge necessary to maintain the varieties over a large number of years. Never plant bentgrasses in eastern Washington lawns because of excessive thatch formation and winter disease problems.MOWING PRACTICES
Mowing height can influence the length of life of lawns and also affect the appearance. The following mowing heights are recommended for grasses in the state of Washington:
THATCH REMOVAL
Power rake good quality lawns if thatch exceeds 1/2 inch in depth. The removal of dead stems and surface roots and accumulated organic debris of all sorts will prevent excessive thatch formation and the necessity for renovation. As thatch builds up in a lawn, the mower tends to run higher from the ground, especially where lightweight mowers are used. Excess thatch can also serve as a home for insects and increased disease development.WATERING PRACTICES
Saturated soils tend to induce surface rooting. Roots will develop where oxygen supplies are greatest and saturated soils have very low oxygen concentrations. Thorough, infrequent watering is much more desirable than light, frequent applications and is regulated by soil texture and depth. Light, frequent applications tend to encourage weedy grasses and certain broadleaf weeds and decrease the quality of desirable grasses. Close observation of the turf will indicate the need for water before wilting or browning occurs. A soil probe can be used to feel the soil for its moisture content.TURFGRASS LOSSES FROM PESTS
Lawns severely damaged by insects, diseases, or uncontrolled weeds may have to be renovated to correct the problem. Discreet and proper use of pesticides as necessary can control these problems, giving longer life and beauty to the lawn as well as being environmentally conscious.RENOVATION PROCEDURE
Favorable spring and fall growing weather will hasten lawn recovery following renovation. Summer renovation may result in slow recovery and is generally not recommended. Total kill, sod removal, and reestablishment can be accomplished during the late summer period.
1. Adjust the mower to approximately 3/4 inch and mow the lawn thoroughly-slightly lower for bentgrasses.
2. Power rake the lawn as many times as may be necessary to remove accumulated thatch. It is best to dethatch in opposite directions. Thoroughness is important.
3. When all thatch has been removed, mow the turf again at approximately 3/4 inch high.
4. Grass stems and crowns may be excessively thinned by heavy raking. If this is the case, over-seed the lawn at a rate of 1/2 the recommended rate of seed per 1,000 square feet for establishment, using varieties recommended for your area.
5. Before overseeding, remove sod from all high and low spots, adjust these areas to the proper lawn grade and replace the sod to obtain a uniformly smooth surface.
6. Growth will initiate quickly from grass stems and crowns that were not removed through the raking process and from the additional seed planted. Although the turf may be somewhat thin, mowing must be practiced regularly at the recommended mowing height. It is important to maintain surface moisture for germination of the newly applied seed.
7. Lawns having large patches of coarse, weedy grasses such as velvetgrass, unimproved tall fescue, orchardgrass, or nonturf type perennial ryegrasses can be best renovated if all vegetation is killed with glyphosate (Roundup®). Apply chemicals in mid- spring or late summer. It will probably take more than one application to kill creeping perennial grasses which have rhizomes. You have a choice of removing the dead sod or following steps 1–6 above for reestablishing new turf. It is advisable to increase the seeding rates recommended for new lawns in this case. One pound of available nitrogen per 1,000 square feet from complete starter fertilizers applied following seeding will hasten establishment. If the soil is extremely sandy, two applications of 1/2 pound each per 1,000 square feet should be made instead of the one 1-pound application to avoid the possibility of nutrient loss.
A good lawn should essentially last a lifetime if properly fertilized, watered, mowed, dethatched and overseeded as needed. Pests should be controlled when diagnosed as being at harmful levels to the turf
area.