Lawn Renovation

Lawn renovation involves restoring a deteriorated turfgrass area to an improved condition. Depending on the condition of the turf, this process can be accomplished without establishing a new lawn. Lawn renovation is time-consuming and expensive and should not be performed unless steps are taken to correct the underlying cause of turf deterioration. Included in this publication is information on problems that cause turf to deteriorate and suggested programs for revitalizing turfgrass areas.

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• Causes of turf deterioration
• Renovation program I
• Renovation program II
• Renovation program III

Causes of turf deterioration

The first step in lawn renovation is to correct the primary cause of turf deterioration. Such things as drought, excessive shade, tree root competition, poor drainage, soil compaction, inadequate fertility, acid soils, weed or insect infestation, disease, thatch build-up, improper mowing, poorly-adapted grass species and cultivars, and others may contribute to poor turf. Most of these problems can be corrected by renovation, proper turfgrass selection, and improved maintenance practices.

Shade problems

Shade problems may require removal of some trees, pruning, and planting turfgrass species that are adapted to shaded conditions. Tree roots may need to be pruned to reduce competition with grasses for water, air, and nutrients.

Poor drainage

Poor drainage can often be corrected by breaking-up compacted soil or through installation of drainage tile. Where surface drainage is insufficient, the site may have to be regraded so that water is removed from the site.

Soil fertility and acidity

You can determine if inadequate fertility or acid soils are limiting turf growth by testing the soil. Soil testing services are available from the Agricultural Analytical Services Laboratory (AASL) at Penn State or through private laboratories. Mailing kits for the AASL tests are available at a nominal fee from the cooperative extension office in your county. Soil test laboratories will provide recommendations for the amounts of fertilizer and lime that need to be applied to the lawn.

Pests

All pests present in the lawn need to be identified and controlled. If you cannot identify these pests, take fresh samples to your county extension office or another knowledgeable source to have them identified. The Penn State Extension publication 'Suggestions for Turfgrass Pest Control' contains information on controlling turfgrass pests. There are a number of other publications with similar information in bookstores and at garden centers.

Thatch

Thatch is a tightly intermingled layer of partially decomposed grass stems and roots which develops beneath the actively growing green vegetation and above the soil surface. Thatch decreases the vigor of turfgrasses by restricting the movement of water, fertilizers, and pesticides into the soil. Turfgrass roots also grow into the thatch and may become desiccated as the thatch dries. Thatch builds up over a period of years and this accumulation must be periodically removed by mechanical means. Thatch removal equipment can usually be rented from garden centers or rental outlets. It is best not to remove all the thatch from the site in one treatment.

Mowing

Most lawns should be mowed at two inches or above and on a regular basis as long as the grass is growing. How frequently you should mow depends on the growth rate of the grass. No more than one third of the total leaf surface should be removed at a given mowing. Thus, if the turf is cut at two inches, it should be mowed when it reaches a height no greater than three inches. Clippings do not need to be removed provided the lawn is mowed on a regular basis. All mowing equipment needs to be sharpened and adjusted periodically.

Species and management

Perhaps the most common causes of lawn deterioration are that turfgrass species were planted that are not adapted to the conditions present at the site or were improperly managed. Other problems include the use of inferior turfgrass cultivars and poor quality seed.

Once the reasons for lawn deterioration are recognized and steps are taken to correct the problems, the renovation program can begin. The following three programs are designed to fit most renovation situations. Some operations may need to be altered or omitted depending on the individual situation.

Renovation program I

(early to mid spring or late summer to early fall)

This program is suggested when the existing population of turfgrasses includes 50% or more desirable turfgrass species; there are no infestations of perennial grass weeds (bentgrass, nimblewill, quackgrass, tall fescue, etc.); and the thatch layer does not exceed ½ inch.

1. Weed Control. As a general guide, if only easy-to-kill broadleaf weeds such as dandelion or plantain are present, 2,4-D may be applied and the seeding may be done in two weeks. A combination of 2,4-D, MCPP, and dicamba is recommended if the weed population contains many different weed species or hard-to-kill weeds such as knotweed, clover, or ground ivy. A six week waiting period will be required following use of this herbicide combination. For other less common weeds, the appropriate herbicides should be applied following the manufacturer's recommendation on the required waiting period prior to seeding. After waiting the prescribed period and assuming adequate weed control has been obtained, you are ready to proceed with the remaining renovation operations. These steps should be followed in sequence as one continuous operation.
2. Mow. Mow area closely (approximately ¾ inch) and remove all clippings, leaves, and other debris by sweeping or raking.
3. Thatch. Thatch is best removed with dethatching equipment with vertically rotating blades or aeration equipment. Dethatch only during periods of cool weather and adequate moisture. Thatch should not be removed during periods of high temperatures, drought, or during late fall when winter desiccation may occur. Maintaining a soil pH between 6.5 and 7.0 will favor microbial activity and break down of thatch.
4. Cultivation. Mechanical aerating machines which remove plugs of soil from the turf area are used to alleviate soil compaction and to prepare a partial seedbed. Aeration should consist of a minimum of eight to ten times over the area. A partial seedbed may also be prepared by using a small disc, a spiking machine, or by severe hand raking. Results with these methods will not be as good as with aeration equipment.
5. Lime. Lime should be applied in accordance with a soil test. If the lime requirement exceeds 100 lb. per 1,000 sq. ft., apply 100 lb. per 1,000 sq. ft. at this time and the remainder the following spring or fall.
6. Fertilizer. Fertilizer should be applied in accordance with a soil test. In lieu of a soil test, apply 20 lb. per 1000 sq. ft. of an 0-20-20 or equivalent fertilizer plus 25 to 30 lbs. per 1000 sq ft of a turf grade 10-5-5 or equivalent fertilizer having 35 percent or more of the total nitrogen as water insoluble nitrogen.
7. Drag. Following cultivation (aeration, etc.) and lime and fertilizer application, drag the area with a large door mat or section of chain link fence to mechanically work lime and fertilizer into the cultivated soil.
8. Seedbed preparation. Repeat the cultivation operation to further prepare the seedbed for seeding. If an aerator is used, six to eight times over will again be necessary.
9. Seeding. A turf type disk seeder is the best tool for seeding. This machine cuts the seed directly into the soil, assuring the firm contact between seed and soil which is necessary for maximum germination. When no disk type seeder is available, uniformly broadcast the seed over the area. The total seed quantity should be divided into two equal lots, sowing one lot in one direction and the second at right angles to the first.Good quality seed of permanent species adapted to the environmental and use conditions should be used. In open sunny areas, a Kentucky bluegrass blend of equal parts of two to five Kentucky bluegrasses should be used. Common Kentucky bluegrass as well as the varieties Pennstar, Fylking, Baron, Birka, Bonnieblue, Adelphi, Majestic, Glade, Sydsport, Plush, Galaxy, Georgetown, Touchdown, and Brunswick are suggested. To obtain relatively fast cover, an improved turf-type ryegrass such as Pennfine, Manhattan, Citation, or Yorktown may be added to the mixture in amounts not to exceed 10 to 15 percent of the total mixture. In areas of partial shade and partial open sun use a mixture of 50 to 65 percent Pennlawn red fescue and 35 to 50 percent Kentucky bluegrasses. Heavily shaded areas having relatively dry soils may be seeded with 100 percent Pennlawn red fescue. Heavily shaded areas with moderately wet soils may be seeded to 60 percent Pennlawn red fescue and 50 percent rough bluegrass (Poa trivialis).
10. Drag. Following seeding, drag the area again to work the seed into the seedbed and to cover the seed with a light layer of soil.
11. Roll. The seed should be firmed into the soil by light rolling.
12. Mulch. Where there is little existing grass, a very light application of straw mulch may be applied to retain moisture and to promote germination. Care must be taken that the mulch is not heavy enough to smother or completely shut off light to the existing grass.
13. Water. The seeded area should be kept moist until the seed has germinated and the seedling plants have become well established.

Renovation program II.

(early to mid spring or late summer to early fall)

For use when the thatch layer does not exceed ½ inch and the existing population of the area includes less than 50 percent desirable permanent turfgrass species and/or there is an infestation of bentgrass, Muhlenbergia, quackgrass, or other grass or grass-type weeds.

1. Weed Control. Under the conditions described it is necessary to use a non-selective herbicide to kill out all vegetation. Glyphosate (Round-up) or paraquat may be used. Paraquat is more toxic to humans than glyphosate and requires a pesticide certification license to buy and use. Seedings may be made safely within a few days following application of glyphosate or paraquat but it is suggested that seeding be withheld until it becomes obvious that a good kill has been obtained.
2. Mow. Same as Program I, number 2.
3. Thatch. Same as Program I, number 3.
4. Cultivation. Same as Program I, number 4.
5. Lime. Same as Program I, number 5.
6. Fertilizer. Same as Program I, number 6.
7. Drag. Same as Program I, number 7.
8. Seedbed Preparation. Same as Program I, number 8.
9. Seeding. If the dead cover is quite dense, it will be necessary to seed with a turf-type disk seeder in order to get the seed in firm contact with the soil. If no dense cover exists, proceed as in Program I, number 9.
10. Drag. Same as Program I, number 10.
11. Roll. Same as Program I, number 11.
12. Mulch. No mulching is necessary as the dead vegetation will serve as a mulch.
13. Water. Same as Program I, number 13.

Renovation program III.

(early to mid spring or late summer to early fall)

For use when the thatch layer exceeds ½ inch.

1. Weed Control. Treat with glyphosate or paraquat as in Program II, number 1 if grass or grass-type weeds such as quackgrass, bentgrass, Muhlenbergia, etc. are present.
2. Thatch Removal. Remove existing sod, including the thatch layer, with a mechanical sod cutter or till with a rotovator and rake out sod and thatch material.
3. Grade. Grade off high spots and fill low spots. It may be necessary to bring in additional topsoil.
4. Lime. Ground limestone should be applied in accordance with a soil test.
5. Basic Fertilizer. Basic fertilizer (phosphate and/or potash) should be applied in accordance with a soil test.
6. Tillage. Work limestone and basic fertilizer into the soil to a depth of four to six inches by tillage.
7. Soil Physical Amendments. If a soil test indicates a low organic matter content, work the recommended amount of organic matter into the soil to a two- to four-inch depth.
8. Starter Fertilizer. Starter fertilizer should be applied in accordance with a soil test and raked lightly into the soil.
9. Seed. Apply seed with a broadcast type of seeder. Do not use a turf-type disk seeder. Seed according to seed recommendations as in Program I, number 9.
10. Cover seed. Lightly rake or drag to cover seed.
11. Firm Soil. Lightly roll to place seed in firm contact with the soil.
12. Mulch. Mulch seeded area with clean straw or marsh hay. For best results mulch heavy enough to completely cover the soil. Remove part or all of the mulch within a few days after seed germination. Where equipment is available, area may be hydromulched with cellulose fiber.
13. Water. Same as Program I, number 13.

Although the above procedures appear quite complex, they are only the first step in renovating the lawn. From this point on, a sound management program must be followed to insure continued improvement of the lawn. Publications on various phases of turfgrass management, such as mowing, fertilization, and irrigation, are available through your local county Agricultural Extension office.