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Establishment, Renovation & Repair

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Turf establishment, by the simplest definition, is the planting of turfgrasses.  There are several different types of planting events, ranging from new plantings (i.e. constructing a new turf area where one did not exist before), to renovation or re-construction of an existing turf area, to overseeding or repairs for established turf.

Mature, well-established turf is most functional as well as most tolerant of pests, use, cultural practices, and environmental stresses.  Well-established turf is also more likely to exhibit a desirable level of appearance.  The goal of most establishment projects, then, is to produce a turf stand that is dense, deeply rooted, and will provide rapid cover and develop to maturity as quickly as possible.

Turf establishment includes not only the act of planting, but also encompasses the period of time between planting and the point at which the turf reaches a reasonable level of sufficiency in terms of development and appearance.  This is commonly referred to as the establishment period. Specialized attention and practices are required during this period to help ensure a successful project.  The length of the establishment period can vary considerably depending on many factors including site conditions, weather conditions, time of year, and turfgrass species/cultivars used.

A solid plan for any establishment project is critical. After a thorough site assessment and following proper turfgrass selection principles to match appropriate turfgrass species and cultivars to site conditions, user expectations, and resources for management, turf establishment has three general phases:

Phase 1 – Site Preparation: evaluation, soil testing, cultivation, grading, amendments, seedbed preparation

Phase 2 – Planting: seeding, sodding

Phase 3 – Establishment Period: post-planting care in terms of mulches, irrigation, mowing, and fertilizer.

objective

Conduct all establishment projects at an appropriate time for the best chance of short- and long-term success.

Figure 2. Cool season turf establishment periods.

Cool-season turfgrass establishment periods figure

Plant during favorable periods whenever possible and avoid stress and pre-stress periods.

  • Temperature is key to the adaptation of grasses (where they grow well), as well as when they grow well (month to month and season to season).
  • Cool-season turfgrass shoots grow best when air temperatures are in the range of 65°-75° F, and cool-season turfgrass roots grow best when soil temperatures are in the range of 55°-65° F
  • Seasonal peaks in growth (spring and late summer) correspond with periods when temperatures are in the favorable range, and growth slows or stops during periods when temperatures are outside of this range (above or below).
  • The most sensible approach, then, is to plant just ahead of the most favorable periods for growth, to align the establishment period with the best possible conditions.
  • Whenever possible, avoid planting seed during stress and pre-stress periods (eg. late spring, summer, late fall).  Planting during these unfavorable periods generally reduces the potential for long-term success, and greater inputs are often required to account for this deficiency.

Recognize that late summer is vastly preferable to spring for planting of cool-season turfgrasses in New England.

  • Although a period of favorable growing conditions occurs in both spring and late summer in New England, a host of additional factors make late summer the ideal planting time:
Table 5. Spring versus late summer establishment.
  Spring Late Summer
Timing: * Best approach is to plant as early as possible, but opportunity varies based on winter/spring transition. Best planting window approximately 3rd week of August to 3rd week of September in Southern New England, on average.
Growth period exposure: Only one brief favorable growth period before the first onset of summer stress. Two favorable growth periods before first onset of summer stress.
Soil moisture: Typically wetter soils (more difficult to prepare).  Less initial need for irrigation. Typically drier soils (easier to prepare). More need for irrigation, particularly during early establishment.
Soil temperature: Cooler soil temperatures (less conducive to seed germination). Warmer soil temperatures (more conducive to seed germination).
Precipitation and evaporative demand: Decreasing precipitation, on average, and increasing evaporation (more water loss). Increasing precipitation, on average, and decreasing evaporation (less water loss).
Weed competition: Increasing competition from annual, warm-season weeds, in particular crabgrass (herbicides normally required for control). Little competition from germinating weeds (herbicides not typically necessary). Only winter annual weeds germinate in the fall.
Herbicide conflicts: Seeding not compatible with applications of several common preemergence herbicides. Preemergence herbicides not commonly applied/necessary during this period.
Cultivation: Cultivation required for planting can stir the soil seed bank during the period of maximum annual weed seed germination. Most appropriate time for annual cultivation practices, often performed in conjunction with planting.
Deciduous trees: Deciduous trees leafing out = increasing shade. Deciduous trees soon to drop leaves = decreasing shade. However, potential exists for leaf accumulation on tiny seedlings.

* In Massachusetts, appropriate times for establishment may vary on parts of Cape Cod and on the islands that warm later in the spring and stay warmer later into the fall.

Account for the establishment rate of the turfgrass species and cultivars used.

  • The overall speed of turf establishment is affected by a number of factors including temperature, moisture, fertility, site conditions, etc.
  • A key trait that influences the length of the establishment period is the inherent establishment rate of the turfgrass species and cultivars used.

A general establishment rate comparison by cool-season turfgrass species is as follows:

Figure 3. A comparison of inherent establishment rates of key cool season turfgrass species.

  • Thus, slower establishing species, such as Kentucky bluegrass, should be seeded earlier during appropriate planting ‘windows’.
  • Slower species will require a comparatively longer period of specialized care during the establishment phase. 
  • With faster species, such as perennial ryegrass, more flexibility in terms of timing is possible. 
  • Faster establishing species are also better suited to overseeding or repairs, when factors such as competition with existing grasses or a need for rapid cover come into play.

Understand that expected returns begin to diminish rapidly in the fall.

  • In fall, average temperatures gradually decrease.  Colder nights have an especially pronounced effect.
  • Both day length and the angle of the sun are decreasing (shorter days and lower levels of available light = less photosynthesis = less vigorous growth and development).
  • At some point in the fall, plant processes begin to shift away from growth and towards preparation for winter.  Thus, grasses planted later in the season will be slower to establish, less hardy, and more susceptible to winter injury.

What about dormant seeding?

  • Dormant seeding is seeding after soil temperatures seasonally fall below the range in which turfgrass seeds germinate (< 40°-45° F).  Dormant seeding should not be attempted until temperatures fall below this range.
  • When late-summer seeding is not an option, dormant seeding may or may not be as effective as an early spring seeding.
  • A gamble… don’t count on it to work every time or as well as seeding at more desirable times! Best for emergencies and last resorts, as opposed to new projects.
  • Follow-up seeding or overseeding may be needed in the spring in cases where conditions have not been favorable for a fully successful dormant seeding.
Table 6. Pros and cons of dormant seeding.
Dormant Seeding Pros Dormant Seeding Cons
Soils drier than in the spring, easier site preparation. A mid-winter warm-up can initiate germination.
Requires less irrigation attention. An open winter can dry out seeds.
Requires less weed control attention. Better for slow-establishing species such as Kentucky bluegrass.
Can emerge earlier in spring and get a jump-start on weeds. Increased seeding rates are necessary (rule of thumb: increase by 50%).

Pay special attention to weeds for spring establishment projects.

  • When turf must be planted in the spring, one of the most significant challenges is competition from increasing annual weed pressure.
  • A number of these weed species have warm-season or C4 physiology, which enables them to thrive under hot and dry conditions. Since cool-season turfgrasses are increasingly stressed under such conditions, warm-season weeds become increasingly and overwhelmingly competitive as spring progresses into summer.
  • The first step to combat this problem with a spring seeding is to plant as early as possible. For the best chance of success, spring seedings are often performed in conjunction with application of pre-emergence herbicides.
  • Several common pre-emergence herbicides are not compatible with seeding, and vice-versa, and many herbicides cannot be used post-emergence for a period of time as well.  The few currently labeled herbicide materials that are compatible with seeding include siduron, mesotrione, and quinclorac.

Specific management approaches for spring weed control can be to the Weed Management chapter of UMass Extension’s Professional Guide for IPM in Turf for Massachusetts.

objective

Properly prepare the planting site to promote rapid and complete establishment.

Have a sound plan for establishment projects, starting with site preparation

  • Use information collected during site assessment to make site modifications, if needed.
  • Establishment projects should include proper soil preparation, which includes soil testing.
  • Since turf is a perennial system, new establishment projects or re-construction projects that ‘open’ the soil present a rare opportunity to fully incorporate lime, fertilizer, and other amendments into the root zone; to install sub-surface features such as drainage or irrigation components; and to alter the grade.

Test existing soil as well as soil or amendments which may be added to the site.

  • Test for chemical characteristics (pH, fertility, nutrient reserves, heavy metals, salinity, etc.).
  • Test for physical characteristics (texture, particle size distribution, percent organic matter etc.).
  • Ensure that any amendment materials are compatible with the soil already present on the site.  Uninformed additions of soil or organic material are strongly discouraged and may lead to problems that are extremely difficult to correct.

For comprehensive details on soil testing and soil fertility, refer to the Soil and Nutrient Management chapter of this document.

Conduct establishment activities in a manner that minimizes adverse environmental impact and potential future compromise to the turf system.

  • Control all weeds, especially difficult perennial weeds.
  • Remove all debris from land clearing and similar operations; never bury debris. Debris left to decay in the soil may result in fairy ring, proliferation of mushrooms, poor drainage, depressions, and stress spots or failures as turf matures.
  • Minimize the amount of land exposed as well as amount of time that soil is bare.
  • Protect exposed soil from erosion. Use temporary groundcovers or cover crops if land will be bare for an extended period. Cover stockpiled soil, and do not leave soil exposed over winter.
  • Protect entryways to water resources (i.e. catch basins and other drainageways) from runoff from exposed and stockpiled soil or amendments.
  • Environmental protection measures may include installation of erosion control barriers such as straw bales, silt fences, berms, and sediment basins. Maintain protection until turf is well established.
  • When conducting sitework with heavy equipment, remove and stockpile topsoil and/or bring in new topsoil. Mix soil and amendments off-site to reduce compaction potential.

Grade properly.

  • Provide for proper water movement and drainage.

Surface drainage: movement of water across the top of the soil, via directed slope.

Internal drainage: downward movement of water into, through and out of the soil profile and drainage features.

  • When grading, it is especially important to consider a range of scenarios, from regular precipitation to extreme storm events, to help ensure that water will move off the site in an effective and environmentally responsible manner under a variety of conditions.
  • When rough grading, match contours of the sub-grade to the desired finished grade.
  • Install underground irrigation and drainage components beneath the sub-grade.
  • Eliminate depressions and pitch the grade away from buildings.
  • Avoid altering the grade around established trees to prevent damage to the root system (no cutting, no filling)
  • Compaction caused by construction activities should be remedied before topsoil is replaced
  • Allow for soil to settle before final grading. Final grading should be done just prior to final bed preparation for seeding or sodding.

Figure 4. Judicious use of surface drainage features can prevent excess moisture problems and pooling and ponding of water. Provide for irrigation and sub-surface and surface drainage, if necessary.

  • Install any sub-surface irrigation components prior to planting if specified and appropriate for the site and the management program.
  • Where surface drainage is not sufficient and where otherwise warranted, sub-surface drainage should be installed.
  • Where possible, and when it will not interfere with the use of the turf, grade to allow turf to take advantage of runoff from impervious surfaces such as parking areas, driveways, and rooftops.

Prepare the root zone.

  • An ideal root zone for a lawn is friable, fertile, and has good infiltration, drainage and water holding capacity.
  • Provide for a minimum 6-inch depth of root zone.
  • When using existing soil, incorporate amendments, fertilizer and liming materials as specified by the results of a soil test. Refer to the Soil and Nutrient Management chapter of this document for additional information.
  • When amending existing soil, rototill in small amounts at a time to achieve uniform distribution.
  • Note that excessive rototilling or rototilling when the soil is wet can damage soil structure.
  • Whenever possible, and when amending with large quantities of materials, remove topsoil and mix with amendments off-site, then replace uniformly mixed/amended soil.

Prepare the final planting bed.

  • The final objective is a firm (not compacted), granular bed for seed or sod.
  • Remove all rocks and debris and ensure a uniform surface.  
  • Drag or hand rake the site if necessary.
  • Irrigate lightly to settle the soil, or roll lightly to firm if needed.

objective

Use a planting method that is appropriate for the site, the budget, and project objectives.

SEEDING

Know that the single most important investment in ensuring high quality turf is the use of high quality seed.

  • Seed cost is relatively low when compared with other turf management inputs.
  • An investment in high quality seed is comparatively small when the potential number of years that a turf stand can persist is considered, as well as the reduction in management inputs often realized with higher quality turf.

Read and understand turfgrass seed labels.

  • To inform and protect the buyer, certain information must be listed on the seed label:
  1. The name of the seller
  2. The lot number: can be used to track the origin of the seed. Useful if a problem develops.
  3. The seed variety or varieties: in some cases, it is legal to list species with only VNS (Variety Not Stated) designation.
  4. Pure seed content (purity): % by weight of each species or variety. A measure of seed quantity, not quality.
  5. Germination percentage: % of each pure seed component that was capable of growth at the time of testing (under ideal conditions).
  6. Date: the date on which the seed was tested. Germination percentage declines with age of the seed.
  7. Crop seed content: Can be more undesirable than weed seeds as a source of contamination. Should be as low as possible!
  8. Weed seed content: % of all seeds that are not pure seed or crop seed. Ideally 0.5% or less.
  9. Noxious weeds: expressed as per pound or per ounce of content weeds officially classified as difficult to manage.
  10. Inert matter: % by weight of all material in the seed that will not grow. Lower inert matter = better value!

For more information, refer to our Understanding a Turfgrass Seed Label fact sheet.

Use certified seed whenever possible.

  • Certified seed must meet minimums for purity and more rigid standards for weed and crop seed content.
  • Seed certification helps to guarantee authenticity of turfgrass varieties.
  • Certified seed carries a color-coded certification tag: blue tag = 95% purity, gold tag = 96-97% purity.

Determine and use an appropriate seeding rate.

  • Proper seeding rate is critical to achieving a functional turfgrass stand that will develop to maturity as quickly as possible.
  • Turfgrass plants compete for space and resources with each other and with potential invaders (weeds).
Lower than optimum seeding rate = Higher than optimum seeding rate* =
An open stand of low shoot density which is less functional and encourages weed invasion. A stand composed of many small plants that are slow to mature and less tolerant of stress.

* Please note that high rate overseeding and repairs, when done properly, is an accepted and successful practice in many sports fields management programs.

  • Optimum seeding rate ranges take into account factors such as: seed size and number per pound, growth habit, minimum purity and germination differences among species.

Large seeds = less seed per pound = higher seeding rate

Small seeds = more seed per pound = lower seeding rate

  • Growth habit affects seeding rate: adhering to at least minimum seeding rates is more important with bunch-type grasses, which have a lower capacity to spread laterally relative to stoloniferous or rhizomatous grasses.
  • The better the conditions for seeding (soil type, seedbed, time of year) the less seed will be needed.
  • As a general rule, seeding rates should be increased by 50% to compensate for poor conditions.

Factors or conditions that contribute to poor germination and seedling survival include:

  • poor soil conditions, including drainage (excessive, poor), improper pH, nutrient deficiency, compaction, salinity.
  • poor seedbed because of inadequate or excessive soil firming, excessive tilling, rocks and debris at soil surface, poor seed to soil contact or coverage, inadequate or excessive mulch, or steep grades that contribute to soil erosion.
  • sub-optimum seeding time, causing late spring/early summer mortality (drought and heat stress, weed competition, and disease) or late fall/early winter mortality (winter desiccation, frost heaves, unfavorable temperature).
  • poor post planting care, consisting of inadequate soil moisture (irrigation), improper mowing and fertilization practices, not controlling traffic, etc.

For specific seeding rate guidelines for turfgrass species and recommended mixtures, refer to the Turfgrass Selection: Species and Cultivars chapter of UMass Extension’s Professional Guide for IPM in Turf for Massachusetts.

Use an appropriate and effective seeding method.

  • Maximize seed to soil contact through every avenue available.
  • Divide seed in half and seed in two directions when possible for maximum coverage and uniformity, using equipment appropriate to the particular site and operation.
  • Drop spreaders are somewhat preferred for precise application (better suited for tight areas and around non-turf areas), rotary spreaders are less precise (better suited for larger, open areas).
  • Spreader calibration is seldom practical for seed.  A general guideline is to start at 20% open/80% closed and adjust as needed (seed is much more forgiving than fertilizers or pesticides).
  • Seed ‘drills’ (BrillionTM-type seeders) are very precise, but best suited for large areas and sod farms
  • Seeding by hand is imprecise and should be avoided with the exception of small repairs.
  • Consider the use of hydroseeding on large or hard to access areas.
  • Careful attention to turfgrass selection, proper use of quality mulch materials, correct application methods, and good follow-up care lead to better long-term results from hydroseeding.  For example, contrary to popular belief, the use of hydroseeding does not typically eliminate the need for attentive irrigation during the establishment period.
Table 7. Pros and cons of hydroseeding.
Hydroseeding Pros Hydroseeding Cons
  • Fast, large areas can be seeded quickly.
  • Especially suited to difficult sites such as roadsides, medians, and steep slopes.
  • Addition of mulch and ‘tackifier’ can help with erosion control.
  • Higher cost than standard seeding
  • Relatively poor seed-to-soil contact.
  • Risk of mulch drying out and forming a hard crust which can inhibit seedling development

SODDING

Consider establishment from sod if the site, project and budget allow.

  • Sodding involves transplanting of turf from one site to another.
  • Fast and effective, but expensive compared to other establishment methods.
  • Can provide opportunities for establishment at times that would otherwise be less than ideal. Sod laid in spring, for example, is better able to compete with annual weed pressure than turf planted from seed.
  • Most appropriate for high value sites, or situations where turf cover is needed very quickly.

Figure 5. When laying sod, seams should be pulled tightly closed. Proper repair steps should be taken for seams that open after installation. Use appropriate methods for sod installation.

  • Specialized care for handling and establishment are required. Sod must be installed ASAP after harvest (normally within 24 hours). Prevent sod rolls or pieces from drying out and protect from overheating prior to installation.
  • Sod can be installed any time soil is not frozen (for best results, soils should be warm enough for root growth: > 50º F).
  • Soil on sod should be as close as possible to soil on site; this reduces the potential for layering problems.
  • Site preparation is the same as for seeding (finished grade; lime and fertilizer according to soil test; firm, granular planting bed), with the planting bed being slightly firmer, but not compacted.
  • Moisten (don’t soak) sod prior to installation.
  • Lay sod by staggering the seams, perpendicular to slope. Stake or staple on slopes greater than 10%.
  • Roll sod lightly to eliminate air pockets and increase soil contact.
  • Irrigate sod deeply as soon as possible after installation, enough to wet the underlying soil and promote good rooting and establishment.
  • Fill in any seams that open with seed/soil/compost “divot mix”.
  • With sod, post-plant fertilizer applications must be delayed until the root system is well developed and has knit strongly into the existing soil.

Know the significance of sod thickness for specialized installations.

  • Sod thickness refers to the amount of soil attached to the sod and does not include shoots or thatch.
  • Sod is often available in various thicknesses, typically ranging from 1/2” to 2”, and also various widths.
  • Different sod thicknesses suit different applications:

Thinner sod = lower cost = lower initial stability = faster establishment
Thicker sod = higher cost = higher initial stability = slower establishment

  • Thicker cut sod is most often used for specialized installations (typically sports fields) and is not necessarily appropriate for lawns.

objective

Provide attentive post-planting care to promote turf growth and development during the establishment period.

Understand that careful attention to moisture during the establishment period is a critical aspect of any planting project.

  • Adequate moisture is required not only to initiate the seed germination process, but also to sustain young seedlings before their root systems are fully developed. In the case of sod, adequate moisture is necessary for the sod to root down into the soil on the site.
  • Too little water will cause seedlings or sod to dry out, which could result in delayed development or death of plants.
  • Too much water can inhibit germination, rooting and shoot growth, promote disease problems (‘damping-off’) and may cause washing of seed and soil.
  • The general approach is to keep the planting site evenly moist but not soggy, and to gradually scale back irrigation as the turf, in particular the root system, develops and matures.
  • At first, water frequently to a shallow depth. As seedlings mature, reduce the frequency of irrigation, but increase duration of each irrigation event to water more deeply, eventually recharging the root zone and allowing the top of the soil to dry between irrigation events.

Figure 6. During establishment, clean, weed-free mulch materials can conserve moisture and help to hold seed and soil on a slope. Use compatible mulches when planting from seed to enhance establishment and protect the soil.

  • The best mulches are weed-free, bio-degradable, and non-smothering.
  • Mulches can be used during establishment to:
    • Retain moisture, and help with tricky water management
    • Help prevent soil erosion, especially on slopes
    • Protect seed/seedlings from movement due to washing or wind
    • Protect seed/seedlings from foraging animals or birds
    • Buffer temperature fluctuations
  • Mulch types:
Loose ‘straw’ mulches Seek out ‘clean’ straw such as oat or barley. Avoid local ‘hay’ due to high potential for undesirable weed seeds.
Straw and wood-fiber netting: Fast, uniform coverage, but higher cost than loose straw options.  Very good erosion control.  Most are bio-degradable, leave-in-place systems.
PennMulchTM or similar products: Made from recycled newspaper and include water-holding polymers, similar to hydroseeding mulch.

Pay particular attention to fertility during the establishment period.

  • Establishing turf uses available nitrogen very quickly... watch for slow growth, yellowing, and other signs of nutrient deficiency.
  • Maintain fertility, especially N, to maintain vigorous growth and prevent deficiency.
  • Rule of thumb: apply an additional 0.5 lbs N/1000 ft2 when establishing turf is 2-3 inches high.
  • In the case of sod projects, post-plant fertilizer applications must be delayed until the root system is well established.  This process may take up to six weeks, or longer.  Nutrients applied too soon will not benefit the plants and have a higher probability of loss to leaching and runoff.

Begin mowing as soon as the turf can withstand traffic.

  • Mowing is a key step for turf establishment, as mowing stimulates tillering which is the primary driver of turf density.
  • When dealing with new turf, the best way to time the first mowing is to use the '1/3 rule’ as a general guideline. 
  • Accordingly, an appropriate mowing height should be determined in advance, and the turf should be cut when it reaches a height around the 1/3 rule threshold.  In other words, when seedlings reach a height about ⅓  higher than desired lawn height, and can withstand traffic, begin to mow to a height appropriate for the species and use.
  • If concern exists about traffic or compaction on the site, opt for smaller lighter walk-behind equipment for the first few mowings, as opposed to larger, heavier riding equipment.
  • The 1/3 rule can also be used to determine the appropriate mowing frequency as the turf matures.

Stay on top of weeds.

  • When feasible, mechanically remove weed infestations from newly established lawns.
  • Annual weeds will eventually mow out of new turf.
  • Follow label instructions of any herbicide carefully to avoid damaging young turfgrass plants.  Ideally, weed control materials should not be applied until turf is well established.
  • Spot treat whenever possible. 

objective

Re-plant when turf performance deteriorates below an acceptable level and cannot be improved through normal cultural practices.

Choose a re-planting approach that fits the situation.

  • There are two general categories of re-planting:

Renovation (less disruptive) – Process of replacing the turf plants on a site without making changes to the soil or grade. Does not normally include total removal of existing turf, but usually includes eradication of the existing stand with non-selective herbicides or extended covering. May include some superficial cultivation in the interest of promoting seed-to-soil contact.

Re-construction (more disruptive) – Involves wholesale removal of existing turf on a site in conjunction with tilling or other soil cultivation, at least to the depth of the root zone or deeper. Frequently includes addition of soil amendments, addition of topsoil, and/or changes to grade.

Choose renovation when turf has deteriorated due to stress, pest damage or unadapted grasses, but the soil and overall growing environment remain generally suitable.

  • A general guideline is to renovate when 50% or more of the turf is composed of undesirable plants (grasses, weeds, etc).
  • Renovation is a great opportunity to more closely match grass species and varieties to site conditions.
  • When circumstances or budget do not permit a justifiable re-construction, a renovation approach will most often yield measurable improvement.
  • Even in situations where the means and need for re-construction exist, opting for renovation first can postpone major disruption and may at best have satisfactory results and at least buy some time (perhaps multiple seasons) before the larger investment of funds and energy in a wholesale re-construction project.
  • Time renovation projects to coincide with an opportune time for turfgrass growth and development.

Evaluate the site prior to beginning the renovation process, and correct any factors that may have contributed to the turf deterioration.

  • The turf may be in poor condition because of unadapted grasses, improper or inadequate maintenance practices, extensive thatch accumulation, excessive disease and/or insect damage, a heavy infestation of difficult-to-control weeds, or a number of other factors.
  • An important step in renovation is to eliminate whatever factors caused poor quality, followed by re-planting. Renovation will only yield temporary improvement unless the original factors that led to poor quality are remedied.

Control all weeds present prior to renovating.

  • Most broadleaf weeds can be selectively eliminated using commonly available herbicides. Spot treatments are preferable to blanket applications, and may be especially possible when infestations are small and/or patchy.
  • Follow label directions for appropriate intervals following herbicide application before proceeding with renovation in order to allow for complete herbicide uptake and to allow any chemical residues in the soil to dissipate.
  • It may be advisable to permit the lawn to grow slightly higher than normal prior to weed control to allow the weeds to grow larger, thus producing more leaf area for better herbicide uptake and control.
  • Small infestations of bunch type (non-spreading), weedy grasses can be removed by digging. Remove the weedy grass and soil to a depth of about 2 to 3 inches. Remove soil for a distance of about 2 to 3 inches outside of the clump to ensure the removal of all parts of the undesirable plant. Spot treatments with a non-selective herbicide that allows for seeding quickly following treatment may also be effective.
  • Perennial weeds which spread via rhizomes (underground creeping stems) or stolons (above ground runners) cannot be controlled by digging and are more effectively controlled using a non-selective herbicide.

Fertilize and lime if necessary.

  • Proper soil fertility and pH are essential for successful renovation.
  • Application rates of fertilizer and lime should be based on soil test results. Soil should be tested well in advance of a renovation project; at least 3 to 4 weeks prior, if possible. For more information, refer to the Soil and Nutrient Management chapter of this document.

Prepare the seedbed.

  • Mow as low as possible, somewhere in the range of 1/2 inch to 3/4 inch is ideal.
  • If there is an appreciable accumulation of thatch (especially if more than 1/3 inch), remove it at this time using a de-thatcher, power rake or vertical mower.
  • To provide a good seedbed and help ensure good seed-to-soil contact, use a de-thatcher set to penetrate the soil to a depth of about 1/4 inch. Smaller areas can be hand-raked to loosen the soil to the proper depth.
  • When raking or dethatching, do not remove more than 50 percent of the dead debris because the remaining debris serves as mulch, which protects against soil erosion and seed displacement, and helps with moisture retention.
  • Remove all loose debris prior to seeding.
  • Power slice seeding is an additional, very effective approach that combines the cultivation and planting steps and yields superior seed-to-soil contact.

Seed the area.

  • Use seed from a mix or blend similar to that existing in the lawn unless improper turfgrass selection was an original contributor to poor quality.  In the latter case, match new species and cultivars to the growing environment on the site, the intended use of the turf, and the management program (see the Turfgrass Selection: Species and Cultivars chapter of UMass Extension’s Professional Guide for IPM in Turf for Massachusetts)
  • Apply seed uniformly over the area to be renovated. In order to insure uniform coverage, apply the seed in two directions made at right angles to each other.
  • Rake lightly following seeding (a leaf rake works well), or drag with a steel mat or door mat to work the seed into the soil to a depth of about 1/4 inch.
  • Roll the area with a light roller if possible to encourage good seed-to-soil contact.
  • If the area being renovated is on a slope, application of weed-free mulch may be necessary to reduce erosion.

Provide follow-up care for the site.

  • Water lightly and frequently, two to three times per day if necessary, to keep the seed bed damp during the period of germination and establishment.
  • When seedlings reach a height about ⅓ higher than desired lawn height, and can withstand traffic, begin to mow to a height appropriate for the species and use.

Consider full-scale re-construction when there are ongoing problems that go beyond just the plants present.

  • Re-construction provides opportunities not typically available in a perennial turf system including ability to fully incorporate fertilizer and soil amendments, improve drainage, and alter the grade.
  • In other instances, digging may be required to remove boulders or buried debris, or to install physical infrastructure such as irrigation system components.
  • Compared with renovation, re-construction is more expensive, time-consuming, labor intensive, and functionally and aesthetically disruptive.
  • Cultivation can damage soil structure, introduce the possibility of soil erosion, and stir the 'seed bank'.
  • In the majority of circumstances, therefore, complete re-construction should be based on identifiable need or, from a strictly agronomic perspective, treated as a last resort.

After tillage and eradication of existing turf, the steps for re-construction are identical to the practices for new establishment outlined in the first part of this chapter.

objective

Use specialized establishment practices to effectively maintain turf cover and density.

Overseed regularly to maintain adequate turf cover and density.

  • Overseeding is the process of introducing seed into a living, often established stand of turf, in order to make repairs or to help maintain adequate turf density.
  • Overseeding is a key practice on heavily-trafficked areas and sports fields.
  • When overseeding is performed to gradually introduce different grass species or cultivars and alter the stand composition over time, it may also be referred to as interseeding.

Use proper overseeding methods.

  • Like renovation, overseeding requires superficial cultivation to expose soil and promote seed-to-soil contact.
  • Common approaches include broadcast seeding following disruptive practices such as aeration, dethatching, or topdressing.
  • Power slice seeding is a very effective, efficient, and minimally disruptive overseeding method.

Take turfgrass selection into account when overseeding.

  • Because of competition with existing, living turf, faster-establishing turfgrass species such as perennial ryegrass are best-suited for overseeding.
  • Slow-establishing grasses, particularly bluegrasses, are more challenging to overseed successfully.
  • For better results with slower grasses, suppress existing turf with moderately close mowing prior to overseeding.
  • Continue mowing regularly; base mowing frequency and height of cut on mature grasses present.

Repair thin or bare patches regularly, on an as needed basis.

  • Loosen soil if necessary or aerate with core aeration or vigorous raking.  ‘Garden Weasel’ type cultivators are an excellent tool for small patches.
  • Apply seed.
  • Topdress with fine finished compost or mulch.
  • Irrigate in the same manner as for new seedings.

Pre-germinate seed for very quick repairs.

  • Place seed into a cloth sack.
  • Submerge sack into a bucket or barrel of water and soak for at least 12 hours. Sufficient time may vary depending on grass species selection.
  • Aerate by lifting the bag out of the water and placing it back several times every few hours, or bubble air into the water.
  • Spread seed out to dry it sufficiently for application in a drop or rotary spreader or a slice seeder.