How Lawns Grow- Growing Your Lawn and Not the Bay! Chuck Schuster Extension Educator University of Maryland Extension 301-590-2807 cfs@umd.edu
You Are The Experts! Nothing has changed in the last 50 years Correct? Fertilizer and mowing recommendations haven t changed.right? Everyone wants the same thing right? BUT.
Lawn Types Most 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 Types Understanding 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 Turf Hydrologic-Diffuse root system holds soil and nutrients Cooling- transpiration helps reduce temperatures. Carbon Sequestration- turf grass captures CO 2 and through photosynthesis convert it to sugars and carbohydrates.
Why Raise Turf? Benefits of Turf Aesthetics- 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.pd f
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 superintendents Public 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) K 2 O- 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 turf Note that turf fertilizer use is fast approaching that of crops in Maryland. Land Use Crops vs. Turf Turf 48.8% Crops 51.2% 1% 1% 2% 3% 7% 1% 1% 1% 0% 0% Turf Acres in 2005 83% Single Family Homes County Government Schools Parks & Athletic Fields Golf Courses Religious Facilities State Highways Sod Farms Apartments Airports Cemeteries
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, setbacks Using Soil testing to determine nutrient needs (See TT116)
The Goal is to Reduce Phosphorus
Optimum Turf growth requires proper management. This Includes Appropriate Nutrient application timing Proper mowing heights
Mowing Heights Turf Type Kentucky Bluegrass Spring and Summer (inches) Autumn and Winter (inches) 2.5-3.0 2.0 Perennial Ryegrass 2.5-3.0 2.0 Tall Fescue 2.5-3.0 3.0 Fine-Leaf Fescue 3.0-4.0 3.0 Zoysia 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 form Use 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 Labels Do 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 Fertilization University 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 Slump When temperatures reach 85 o 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 Fertilization Nutrients 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 50 o F.
Fall Fertilization Roots continue to grow until the soil reaches 32 o F. The best time to fertilize cool season grasses is between Halloween and November 15*. *new laws
Fertilization Late 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 or GrassCycling 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 or GrassCycling It encourages a healthier lawn by returning nutrients to the soil, in a slow release form
Clipping Management or GrassCycling Saves time by eliminating the need to bag or rake grass clippings
Clipping Management or GrassCycling Helps protect the environment by reducing the amount of lawn clippings in the landfill
Tips on Grasscycling Mow with sharp blades Mow lawn when dry
Mowing For Fescue and Bluegrass: Mow 3 to 3 1/2 inches Keeps grass greener in summer Roots are healthier, soil is cooler Thatch 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.
Keep Blades Sharp! Mowing 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 nutrients become 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 Occur Bluegrass lawns are most susceptible to drought damage Tall fescue can sustain damage If normally watered in shallow, frequent amounts More stress will occur on grass cut short If drought is severe (use footprint test)
If You Must Water Apply water so that is wets at least 6 inches deep into soil (approximately one inch of water) Water in evening (not night) or early morning Avoid windy periods
Reseeding Apply seed of improved variety. https://marylandturfgrasscouncil.wildapricot.org/resour ces/documents/tt%20bulletins/tt- 77%20Recommended%20Turfgrass%20Cultivars%20F or%20certified%20sod%20production%20and%20se ed%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 Renovation Add 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 Renovation Apply seed of improved variety. Spread and rolled. Seeds will need a watering program to be of any value
Core Aeration
Aeration Aeration 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.
Core Type Aerator Slit Type Aerator
Why Aeration Works
Warm Season Grasses Lay dormant when average temperature is below 70 F. Thrive with warmer temperatures. Tolerate moisture stresses much better. Then why doesn t the average homeowner want it?
Prefer dryer soils Warm Season Grasses Can tolerate closer mowing heights. Tend to handle heavy traffic areas better.
Warm Season Grasses Warm season grasses turn brown when dormant, the lawn does not have the lush appearance desired.
Conclusion Know 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
cfs@umd.edu QUESTIONS?