How Lawns Grow- Growing Your Lawn and Not the Bay!

Chuck SchusterExtension Educator

University of Maryland Extension301-590-2807cfs@umd.Edu

You Are The Experts!Nothing has changed in the last 50 years

Correct? Fertilizer and mowing recommendations havent

changed .right?Everyone wants the same thingright?BUT.

Lawn TypesMost lawns grown in the Mid Atlantic Region are

cool season grasses, fescues, bluegrass, ryegrasses.Warm season grasses are used in certain locations.

Warm season grasses include Zoysia and Bermuda.

HOW CAN I TELL THE DIFFERENCE???

Lawn TypesUnderstanding which lawn types you are working

with determines mowing height, watering needs, and fertilizer requirements.

Before doing anything, determine the type of turf you are working with, warm or cool season turf!

Why Raise Turf?

Benefits of TurfHydrologic-Diffuse root system holds soil and nutrientsCooling- transpiration helps reduce temperatures.Carbon Sequestration- turf grass captures CO2 and through

photosynthesis convert it to sugars and carbohydrates.

Why Raise Turf?

Benefits of TurfAesthetics- desired by homeowners, creates a park like

setting, quiets noise.Safety- while much discussion on use of artificial turf still

exists, most agree that a high quality natural turf decreases sports injuries

Oxygen- a 50 x 50 foot lawn produces enough oxygen for a family of four. In Maryland, 1.15 million acres of turf generate enough oxygen for about 80 million people.

What Makes a Lawn Grow?Cool Season Grasses

Good soil ( this is hard to change)

Proper moisture, and drainage

Proper aeration

Appropriate nutrients

The Growing Year Cool Season Grasses

The Growing Year From Late November until Mid February, the lawn is

Dormant. As March approaches the root system starts to become

active. The top of the turf starts to show life during late March

and into April. 60% of all top growth occurs from April through Mid

June Summer Stress Slows Growth from Mid June Through

August

The Laws That Govern

Chesapeake Bay Phosphorus Reduction Act of 2009

Established the use of low phosphorus fertilizer on turf. Phosphorus cannot exceed 5% for existing

turf and products above 5% P2O5 must have a new label to indicate Not for use on Established

Lawns or Grass

The Laws That Govern

Fertilizer Use Act of 2011 - Created licensing of Urban Land Managers before they may apply nutrient to non agricultural

properties.http://mda.maryland.gov/SiteAssets/Pages/fe

rtilizer/MDAProLawnCareManual6.24.13.pdf

Fertilizer Use Act of 2011

Designed to reduce the amount of nutrients washing into the Chesapeake Bay

Established a licensing requirement for all urban turf managers- a nutrient applicator

license. (very different than a pesticide license)

Who Does this Law Affect? Lawn care professionals

Golf course superintendentsPublic Park

Recreational areas Any other non agricultural source

(homeowners)

What Does the Law Limit?

Lawn fertilizers:Phosphorus Nitrogen

Not Limited by the Act

Timing of application Lime to correct pH (though pH will affect availability of

nutrients)K2O- not limited but should only be used as

needed- currently not noted as a potential pollutant.

Training, Certification, Licensing for Professionals

Any one that is hired to apply fertilizer to turfNote that turf fertilizer use is fast approaching

that of crops in Maryland.

83%

7%

3%2%

1%1%

1%1%

1%

0%

0%

Turf Acresin 2005

Single Family HomesCounty GovernmentSchoolsParks & Athletic FieldsGolf CoursesReligious FacilitiesState HighwaysSod FarmsApartmentsAirportsCemeteries

Land Use Crops vs. Turf

Turf 48.8%Crops 51.2%

Chart1

Single Family Homes

County Government

Schools

Parks & Athletic Fields

Golf Courses

Religious Facilities

State Highways

Sod Farms

Apartments

Airports

Cemeteries

Turf Acres

Turf Acresin 2005

936900

78200

38400

21800

16400

9400

9000

8000

7500

5000

4200

Sheet1

SectorTurf Acres

Single Family Homes936900

County Government78200

Schools38400

Parks & Athletic Fields21800

Golf Courses16400

Religious Facilities9400

State Highways9000

Sod Farms8000

Apartments7500

Airports5000

Cemeteries4200

Sheet1

Turf Acres

Turf Acresin 2005

Sheet2

Sheet3

Homeowners No longer able to purchase P bearing lawn fertilizer

without a soil test. Restricts use of nitrogen fertilizers between November

16 and March 1. Enforcement to be done by local municipalities. Educational Programs

Best Management Practices-timing, setbacksUsing Soil testing to determine nutrient needs (See TT116)

The Goal is to Reduce Phosphorus

Optimum Turf growth requires proper management.

This IncludesAppropriate Nutrient application

timingProper mowing heights

Mowing HeightsTurf Type Spring and

Summer (inches)

Autumn and Winter (inches)

Kentucky Bluegrass

2.5-3.0 2.0

Perennial Ryegrass 2.5-3.0 2.0Tall Fescue 2.5-3.0 3.0

Fine-Leaf Fescue 3.0-4.0 3.0Zoysia 0.5- 1.0 0.5-1.5

Decrease nitrogen

Reduce total amount of nitrogen to a lawn/turf

20% must be in a slow release formUse your state recommendations for

predominate species of turf in a lawn.

Reduce Nitrogen

Fertilizer can no longer be used as a de-icer.Never apply fertilizer to frozen

ground, even if the date is met.

New Statements on LabelsDo not apply near water, storm drains

or drainage ditches. Do not apply if heavy rain is expected. Apply this product only to your lawn and sweep any product that lands on the driveway, sidewalk, or street, back onto your lawn.

Spring Fertilization Increases top growth (and mowing) at the expense

of root growth. Produces a turf more susceptible to insects and

disease.Lack of root development increases risk during

drier times of late summer.

Spring FertilizationUniversity of Maryland Recommendations indicate

spring fertilization can occur 1 month before top growth starts through early June and Late August through 6 weeks after first killing frost.

These recommendations allow for the fertilizer to be used to green up the turf.but

Fall fertilization provides the greatest root growth.

The Summer SlumpWhen temperatures reach 85o F and above the

growth slows for cool season grasses.

Summer weeds will germinate at this time.

Crabgrass is an excellent example of a summer weed that will compete with cool season grasses.

The Summer Slump

Summer heat with lower moisture levels may cause cool season grasses to go dormant.

Cool season grasses will again turn green and start active growth when temperatures decrease and soil moisture is replenished.

Fall FertilizationNutrients are used to support root growth. Plants build a reserve to help survive the cold of

winter and to start out the spring season.Top growth stops in the fall when the average

temperature reaches 50o F.

Fall Fertilization

Roots continue to grow until the soil reaches 32o F.The best time to fertilize cool season grasses is

between Halloween and November 15*. *new laws

FertilizationLate spring fertilization can promote top growth.

Heavy top growth helps shade out weeds when mowing height is maintained high.

Remember that fertilization at this time of year does not promote root growth!

And be sure to apply it correctly

Clipping Management-GrassCycling

Cut the lawn so that the clippings are blown into the lawn, not onto the road and sidewalk. Sweep or blow clippings into turf if necessary

Clipping Management orGrassCycling

Grass clippings contribute to healthy turf and healthy biological soil system

Returning grass clippings credits the lawn with as much as one pound of nitrogen per year.

Clipping Management orGrassCycling

It encourages a healthier lawn by returning nutrients to the soil, in a slow release form

Clipping Management orGrassCycling

Saves time by eliminating the need to bag or rake grass clippings

Clipping Management orGrassCycling

Helps protect the environment by reducing the amount of lawn clippings in the landfill

Tips on GrasscyclingMow with sharp bladesMow lawn when dry

Mowing For Fescue and Bluegrass:Mow 3 to 3 1/2 inchesKeeps grass greener in summerRoots are healthier, soil is coolerThatch is reduced

Mow frequently, removing no more than 1/3 of the height

Grass clippings are a natural way to return Nitrogen to the soil.

Mowing Turf mowed high helps to shade weeds out. Reduce weeds

by 50-80%Never remove more than one third of the total

plant in any mowing.

MowingKeep Blades Sharp!Dull Mower Blade - is a very common problem

in lawns. If the mower blade is dull, it will tear off the grass blade instead of giving it a clean cut. This increases the chances of disease infection and leaves a brown tinge to the lawn.

Water helps nutrientsbecome pollutants

Water flowing from the landscape can carry Sediments Nutrients

that pollute our waterways.

Avoid watering turf when possible 1 inch over my 10,000 square feet of grass is 6234 gallons = 20

days of water for a family of 4. Municipal water usually costs you twice Turf will go dormant if you allow it to.

New turf often needs water to survive Well established turf may suffer if the soil profile is poor

Drought can harm some turf Water is required to establish turf, even from sod

When Harm Can OccurBluegrass lawns are most susceptible to drought

damageTall fescue can sustain damage If normally watered in shallow, frequent amountsMore stress will occur on grass cut short If drought is severe (use footprint test)

If You Must WaterApply water so that is wets at least 6 inches deep

into soil (approximately one inch of water)Water in evening (not night) or early morningAvoid windy periods

ReseedingApply seed of improved variety.https://marylandturfgrasscouncil.wildapricot.org/resour

ces/Documents/TT%20Bulletins/TT-77%20Recommended%20Turfgrass%20Cultivars%20For%20Certified%20Sod%20Production%20And%20Seed%20Mixtures%20In%20Maryland.pdfPower seeder can be used.

Seeds will need a watering program to be of any value

Complete Renovation

For weak or undesirable varieties, to repair weed-choked lawn, evidence the soil is poor.

Kill off all green plants in the Fall.

Complete RenovationAdd soil amendments as needed and till into soil

(can be a very physical job on old and compacted soil)

Dead turf will need nitrogen. New seeds will require phosphorus (starter fertilizer).

Complete RenovationApply seed of improved variety. Spread and rolled. Seeds will need a watering program to be of any

value

Core Aeration

AerationAeration helps the lawn's health and vigor, and

it reduces maintenance requirements. The following are other benefits of aeration: Improves air exchange between the soil and the

atmosphere Enhances soil water uptake Improves fertilizer uptake and use

Aeration

Improves turf grass rooting Reduces soil compaction Enhances heat and drought stress tolerance Accelerates thatch break down

When Should Aeration Be Done?Aeration can be done spring or fall.

Annual aeration is beneficial for most lawns.

Lawns growing on heavy clay or sub-soils, and lawns exposed to intense use benefit from more than one aeration each year.

When Should Aeration Be Done?Aeration creates the growth zones new roots need

to achieve the maximum benefit from the season.

Aeration before or at the time of late season fertilization enhances root growth and response and improves spring green up and growth.

Slit Type Aerator

Core Type Aerator

Why Aeration Works

Warm Season GrassesLay dormant when average temperature is below

70 F.Thrive with warmer temperatures.Tolerate moisture stresses much better.Then why doesnt the average homeowner want it?

Warm Season Grasses Prefer dryer soils

Can tolerate closer mowing heights.

Tend to handle heavy traffic areas better.

Warm Season GrassesWarm season grasses turn brown when dormant,

the lawn does not have the lush appearance desired.

ConclusionKnow what type of turf you are dealing with. Soil test to determine Phosphorus and Potassium

needs. Fertilize at the appropriate time.Mow at a height to benefit the turf and not the

weeds.Keep mower blades sharp.Consider Aeration

QUESTIONS?

cfs@umd.edu

How Lawns Grow- Growing Your Lawn and Not the Bay!You Are The Experts!Lawn TypesLawn TypesWhy Raise Turf?Why Raise Turf?What Makes a Lawn Grow?Cool Season GrassesThe Growing Year Cool Season GrassesThe Growing YearThe Laws That Govern The Laws That Govern Fertilizer Use Act of 2011 Who Does this Law Affect? What Does the Law Limit?Not Limited by the ActTraining, Certification, Licensing for ProfessionalsHomeowners The Goal is to Reduce PhosphorusSlide Number 19Mowing HeightsDecrease nitrogen Reduce Nitrogen New Statements on LabelsSpring FertilizationSpring FertilizationThe Summer SlumpThe Summer SlumpFall FertilizationFall FertilizationFertilizationAnd be sure to apply it correctlyClipping Management-GrassCyclingClipping Management orGrassCyclingClipping Management orGrassCyclingClipping Management orGrassCyclingClipping Management orGrassCyclingTips on GrasscyclingMowing MowingMowingWater helps nutrientsbecome pollutantsAvoid watering turf when possibleWhen Harm Can OccurIf You Must WaterReseedingComplete RenovationComplete RenovationComplete RenovationCore AerationAerationAerationWhen Should Aeration Be Done?When Should Aeration Be Done?Slide Number 54Why Aeration WorksWarm Season GrassesWarm Season GrassesWarm Season GrassesConclusionQuestions?