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Renovation of Lawns

Lawn renovation involves restoring a deteriorated turfgrass area to an improved condition. This time-consuming process should not be undertaken unless steps are taken to correct the underlying cause of turf deterioration. This publication includes information on the causes of turf deterioration and suggests programs for revitalizing turfgrass areas.
Lawnmower cutting grass.

Lawnmower cutting grass.

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.

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 lawn.

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 Penn State 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.

Weeds, diseases, and insect pests

Weeds, diseases and insect pests present causing the lawn to deteriorate need to be identified and managed. If you cannot diagnose the problem(s), take a fresh sample to a knowledgeable source to have it identified or search the internet for websites and/or books with photographs on turfgrass weeds, insects, and diseases.

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

Lawns should be mowed above 2 inches 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. During peak periods of growth in spring, lawns may need to be mowed more than once per week. During periods of drought, your lawn may not require mowing until active growth resumes following rainfall events. Clippings do not need to be removed provided the frequency of mowing is adequate. All mowing equipment should be properly adjusted and cutting blades should be periodically sharpened.

Turfgrass species selection 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, etc.); and the thatch layer does not exceed ½ inch.

  1. Soil test. Be sure to take a soil test 3 to 4 weeks in advance of renovation activities. 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 Penn State Extension office in your county.
  2. Weed control. A herbicide containing a combination of 2,4-D, MCPP, and dicamba is suggested if broadleaf weed species such as dandelion, knotweed, clover, or ground ivy are present in the lawn. A waiting period of about 4 weeks will be required following use of this herbicide combination before seeding can begin. Be sure to follow the manufacturer's recommendation on the label concerning the specific interval between herbicide application and seeding. Because of the long waiting period following herbicide application, broadleaf weed control is best done well in advance of the optimum time for seeding. After waiting the prescribed period and assuming adequate weed control has been obtained, you can proceed with the remaining renovation operations. These steps should be followed in sequence as one continuous operation.
  3. Mow. Mow area closely (approximately ¾ inch) and remove all clippings, leaves, and other debris by sweeping or raking.
  4. Thatch. Thatch is best removed using dethatching equipment with vertically rotating blades or core aeration equipment. Remove thatch 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.
  5. Cultivation. Mechanical core aerating machines which remove plugs of soil from the turf area can be used to alleviate soil compaction and to prepare a partial seedbed. Aeration during a renovation program should consist of eight to ten passes over the area with a core aerator.
  6. Lime. Lime should be applied in accordance with a soil test recommendation either just before or immediately after cultivation. 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. 
  7. Drag or slice. Following cultivation and application of lime (if needed), drag the area with a large mat or weighted section of chain link fence to break up cores and work lime into the cultivated soil. Alternatively, use a vertical slicing machine to break up the cores. Wait until soil cores have dried before dragging or slicing.
  8. Fertilizer. If seeding, apply a starter fertilizer at the rate recommended on the fertilizer label. Starter fertilizers contain nitrogen, phosphorus, and usually some potassium.  Nitrogen and phosphorus are particularly helpful for rapid turf establishment. Depending on the results of your soil test, additional phosphorus and potassium may be beneficial for new seedings. These nutrients should only be applied in accordance with a soil test. 
  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 seeder is available, uniformly broadcast the seed over the area, preferable with a drop seeder. 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 turfgrass species adapted to the environmental, managment, and use conditions at the site should be used. In open sunny areas, good cultivars of Kentucky bluegrass, turf-type tall fescue, or perennial ryegrass can be used. In areas of partial shade and partial open sun a good quality turf-type tall fescue  or a mixture of a fine fescue (creeping red fescue, Chewings fescue, or hard fescue) and Kentucky bluegrass can be used. Heavily shaded areas having relatively dry soils may be seeded with 100 percent fine fescue.

  10. Roll. The seed should be firmed into the soil by light rolling.
  11. 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.
  12. 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 perennial weed grasses such as bentgrass, nimblewill, or, quackgrass.

  1. Soil test. Take a soil test 3 to 4 weeks in advance of renovation activities. 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 Penn State Extension office in your county.
  2. Weed control. Under the conditions described it will probably be necessary to use a non-selective herbicide to kill all vegetation in the lawn. Glyphosate-containing products are suggested for this purpose. Turfgrass seed may be safely applied within a couple of days following application of glyphosate but it is suggested that seeding be withheld until it becomes obvious that a good kill of existing vegetation has been obtained.
  3. Mow. Same as Program I, number 3.
  4. Thatch. Same as Program I, number 4.
  5. Cultivation. Same as Program I, number 5.
  6. Lime. Same as Program I, number 6.
  7. Drag. Same as Program I, number 7.
  8. Fertilizer. 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. Roll. Same as Program I, number 10.
  11. Mulch. Typically, no mulching is necessary as the dead vegetation will serve as a mulch. If there is little existing grass in an area, a very light application of straw mulch may be applied to retain moisture and to promote germination.
  12. Water. Same as Program I, number 12.

Renovation program III

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

For use when the thatch layer exceeds ½ inch.

  1. Soil test. Be sure to take a soil test 3 to 4 weeks in advance of renovation activities. 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 Penn State Extension office in your county.
  2. Weed control. Treat with glyphosate  as in Program II, number 2 if perennial grass weeds such as quackgrass, bentgrass, nimblewill, etc. are present.
  3. Thatch removal. Remove existing sod, including the thatch layer, with a mechanical sod cutter or till with a rototiller and rake out sod and thatch material.
  4. Grade. Grade off high spots and fill low spots. It may be necessary to bring in additional topsoil.
  5. Lime. Lime should be applied in accordance with a soil test recommendation.
  6. Basic fertilizer. Phosphorus and/or potassium fertilizer should be applied in accordance with soil test results.
  7. Tillage. Work lime and fertilizer into the soil to a depth of 4 to 6 inches by tilling.
  8. Soil physical amendments. If a soil test indicates low organic matter content, work the recommended amount of organic matter into the soil to a 2 to 4 inches in depth.
  9. Starter fertilizer. Starter fertilizer should be applied in accordance with a soil test recommendation and raked lightly into the soil.
  10. Seed. Apply seed with a drop-type spreader. Seed according to seeding suggestions as in Program I, number 9.
  11. Cover seed. Lightly rake to cover seed.
  12. Firm Soil. Lightly roll to place seed in firm contact with the soil.
  13. Mulch. Mulch seeded area with clean straw or other mulching material. For best results mulch heavy enough to 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.
  14. Water. Same as Program I, number 12.

The above procedures are only the first steps 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 are available through your county Penn State Extension office.

This publication was originally prepared by John C. Harper II and revised by Peter Landschoot, Professor of Turfgrass Science.

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Title

Renovation of Lawns

Code

UC206

Cost

Free

This publication is available in alternative media on request.

Contact Information

Peter Landschoot
  • Professor of Turfgrass Science
Email:
Phone: 814-863-1017