Florida Friendly Lawn Management Laurie Trenholm, Ph.D. Urban Turfgrass BMP Specialist UF IFAS

2018 MG Turfgrass Field Day Tues, Oct 16 9am 3pm Plant Science Research and Education Unit 2556 Hwy 318, Citra FL Morning research plot tours, afternoon indoor education sessions Meet the IFAS turfgrass researchers and pick their brains! 2

Our Florida Lawn Grasses

Advantages Bahiagrass (Paspalum notatum) Good drought tolerance Low fertility requirements Low maintenance Tolerant of sandy, infertile soils Establishes from seed

Bahiagrass Disadvantages Produces abundance of seedheads Open growth habit encourages weed competition Susceptible to mole crickets Coarse stems are difficult to mow Not wear tolerant

Centipedegrass 6

Centipedegrass Poor man s grass very low input Watch fertilizer very low rates needed and too much leads to centipede decline Few insect and disease problems Light green color Slow growing and prostrate New cultivar Hammock developed primarily for use in south FL

St. Augustinegrass (Stenotaphrum secundatum)

St. Augustinegrass Best shade tolerance of warm season grasses, but varies by cultivar Good salt tolerance Tolerates wide range of soil ph Establishes quickly from sod Deep green color Requires irrigation much of the year to stay green and healthy Chinch bugs becoming resistant to pesticides

Sugarcane Mosaic Virus Outbreaks multiplt counties around the state Floratam most affected cultivar and will usually result in death More resistant Palmetto and BitterBlue, which may get the virus but do not suffer the damage as Floratam No chemical treatments available 10

St. Augustinegrass Cultivars Floratam Bitter Blue Palmetto Delmar Seville Captiva

Empire Zoysiagrass

Zoysiagrass Low growing, dense Very responsive to nitrogen lower rates needed than for St. Aug Shade tolerance similar to Floratam Hunting billbug pests Susceptible to large patch disease Tends to get thatchy Needs about same amount of water as St. Aug Mowing height 2 2.5 Empire most commonly used, but other cultivars in small amounts of production

Empire Zoysiagrass Goes into dormancy throughout winter in central and northern Florida Greens up slowly in spring (large patch issues can compound this) People will want to apply extra N fertilizer to green it up this is not good! Homeowners managing this grass themselves will have to become more familiar with disease management

Nutrients Required for Turfgrass Growth From Environment: Carbon Hydrogen Oxygen

Nutrients Needed From Soil or Fertilizer Macronutrients: Primary: Nitrogen Phosphorus Potassium Secondary: Calcium Magnesium Sulfur Micronutrients: Iron Manganese Boron Copper Molybdenum Zinc Nickel 16

Why Fertilize? Lawns need nutrients to grow in a healthy condition Grasses grow and turn green in response to fertilizer A properly fertilized lawn is your best defense against weeds A properly fertilized lawn is your best protection against storm water runoff This does not mean overfertilization!

When to Fertilize? 1 4 times a year: Spring when growth begins and after danger of frost Summer apply iron or low amounts of nitrogen fertilizer fertilizer important during times of growth, but may not be needed depending on soil characteristics and grass species Fall potassium beneficial, imparts cold tolerance to grass Winter depends on location in state DO NOT fertilize dormant grass with nitrogen (no fertilizer mid Oct April in North Fl and Nov end of March in central Fl) South Florida may fertilize year round

Warm Season Grass Growth 19

What About Other Nutrients? Soil test can tell you what is needed Turf need for calcium & magnesium low In high ph soils, iron & manganese may be limiting for best results, these should be applied in a chelate form (not oxide form)

Annual Fertilization Rates for Lawngrasses (Lbs. of N per 1,000 sq. ft.) Central North Bahiagrass: 1 3 1 3 Centipedegrass: 0.4 3 0.4 2 St. Augustinegrass: 2 5 2 4 Zoysiagrass: 2 4* 2 3 Most zoysia cultivars should get no more than 2 lbs yearly 21

How Much to Apply Each Time Frequency of application: 1 4 times yearly Each application: maximum amount to apply is 1 lb N per 1,000 sq. ft. if fertilizer has slow release N Only fertilize during the growing season 22

Fertilizer Calculations Divide your yard up (front, back, sides) Determine square footage of each area 40 25 23

Fertilizer Calculations Look at fertilizer analysis on bag (ex. 15 0 15) Take the amount of N (15% in this case) and divide it into 100. This gives you 6.6 this is the pounds of fertilizer that you need for 1,000 sq. ft. to apply 1 lb. N This works for ANY fertilizer analysis 24

Fertilizer Calculations To apply the correct amount: Take half of the total amount of fertilizer: 15% = 6.6 lbs fertilizer per 1,000 square feet Half of this = 3.3 lbs fertilizer in spreader 25

Fertilizer Calculations To apply the correct amount: Take the remaining 3.3 lbs, put in spreader and go back and forth at 90 o angles 26

Two Ways That Fertilizers Can Pollute 1. Leaching through soil profile this is what nitrogen will do in sandy soils

Two Ways That Fertilizers Can Pollute 2. Surface water run off

Turfgrass Fertilizer BMPs Keep fertilizer off impervious surfaces Maintain a buffer zone around water bodies Apply only the correct amount more is not better! Soil test know your ph and soil available nutrients Low (or no) phosphorus! Only fertilize during the growing season Irrigate fertilizer in with about ¼ of water Do not fertilize newly planted grass for 30 60 days

Sweep Up Fertilizer Spills

200 linear feet X 5 feet wide mower = 1,000 ft2 2,000 grams clippings (dry weight) 3.5% nitrogen in the clippings = 70 grams nitrogen = 0.15 lbs nitrogen

Nitrate Leaching from New vs. Established Grass in 2005 400 25 300 200 100 0 2-May 16-May 23-May 1-Jun-05 7-Jun-05 14-Jun-05 20 june 28-Jun-05 Newly Planted Sod 5-Jul-05 0.5 1 2 20 15 10 5 0 0.3 lb 0.66 lb 1.3 lb 2.0 lb Established Sod

Nitrogen Rate Study Nitrate N Leaching from Floratam 5 4 3 2 1 0 1 lb N 4 lb N 7 lb N 10 lb N Yr 1 FC1 Yr1 FC2 Yr2 FC1 Yr2 FC2 Yr2 FC3 Yr2 FC4 Yr3 FC1 Yr3 FC2 Yr3 FC3 Yr4 FC4 NO3- N Leached (kg ha -1 ) Nitrogen applied as 100% soluble urea Trenholm et al. 2009

Irrigation BMPs 34

Overwatering Increased disease issues Root rot and stunting Weak turf stand Increased weeds 35

How Frequently to Water Varies due to: Season Soil type Shade Rooting depth Insect or other pests Other stresses

Seasonal Frequency of Irrigation Zazueta, Miller, and Zhang*: Winter 4.5 11.6 Spring 2.7 6.9 Summer 2.7 2.9 Fall 4.8 11.6 *For St. Augustinegrass with a 6 root system under low irrigation regime in the Tampa Bay area

Irrigation Frequency Watch grass for signs of stress Follow watering restrictions! You may water hot spots with hose if needed and if not prohibited by local restrictions

How Much to Water Apply 1/2 to 3/4 when turf shows symptoms of wilt This should not vary only frequency varies!

Short, frequent irrigations Longer, less frequent irrigations

Irrigation System Efficiency Calibrate systems to ensure uniform coverage Check for broken heads, etc Check for landscape plants that may block sprinkler from reaching grass

Time Line for Irrigation for New Sod Plantings Time Frequency Duration First 7-10 days 2-3 times daily 7-10 days after planting Once a day Next 7-10 days Every other day Short (5-10 mins) try to keep plant material from drying out Apply ~ ¼ water more will be wasted due to short roots Apply ~1/4 to ½ of water 3-4 weeks after planting 1-2 times weekly Apply ~ ½ water

Which Grass Has Better Drought Tolerance? All of our grasses need water to stay green (about the same amount!) Survival often depends more on soil organic matter, shade, rooting depth than species

Severe Watering Restrictions Do soil amendments help? Research on these is often not clearly stated Often, no significant benefits seen When possible, incorporate organic matter prior to planting sod/seed Not practical to try to topdress after turf establishment to add organic matter

Mowing 45

Mowing BMPs Mow at the correct height for the species Mowing too low stresses the grass and forces it to use up all saved reserves for shoot growth Mowing high increased root depth

Mowing Heights St. Augustinegrass Standard Height Cultivars: Floratam, Bitter Blue, Classic, etc. 3.5 4 St. Augustinegrass Dwarf Cultivars: Captiva, Delmar Seville 2 2.5 Bahiagrass: 3 4 Centipedegrass: Zoysiagrass: ~2

Mowing Only remove 1/3 of the leaf blade at any one time Grass at 6 should have no more than 2 removed Keep mower blades sharpened Do not mow wet grass Commercial mowers should be washed off between properties (do you ever see this?)

Scalping is a Major Stress

Two Types of Stresses Biotic Insect Disease Nematode Weed Abiotic Drought or over watering Excess or insufficient fertilization Mowing (scalping, dull blades) Soil compaction/ph or other soil issue Temperature extremes Shade Traffic Dog Spots Standing water/submersion Saline (recycled/ocean) or poor quality water

Managing Turf in the Shade Remove shade sources (trimming trees) Reduce traffic in shaded areas Increase mowing height if possible more shoot tissue for photosynthesis will help turf perform better Reduce irrigation in shaded areas Reduce fertilization trying to promote shoot growth with high fertility will further stress the grass

Shade Tolerant Turf St. Augustinegrass = zoysiagrass Centipedegrass Bahiagrass Bermudagrass = Seashore paspalum

St. Augustinegrass Shade Tolerance Seville, Delmar, Captiva Bitterblue Palmetto Floratam

The New Urban Soils Retention pond soils typically very high ph 8 or higher Become very compacted impedes root growth 55

Dealing With High ph 56

Dealing With High ph Micronutrients iron, manganese not available Phosphorous may also be limiting Micronutrient deficiencies cause interveinal chlorosis 57

Dealing With High ph Difficult to lower ph effectively Elemental sulfur forms sulfuric acid in presence of sulfur oxidizing bacteria Short term duration Organic matter humus, peat, peat moss Ammonium sulfate as N source 58

Dealing With High ph Application of ammonium sulfate, biosolids as N source Topdress with compost, organic matter Application of soluble or chelated iron and manganese Foliar fertilization (N and micros) Watch for P deficiency 59

Compacted Soils Lack of oxygen for roots Roots can t grow Water, other inputs can t penetrate Can form solid hardpan layer Dries out Low microbial activity 60

Dealing With Compacted Soils Aerate/topdress Consider foliar fertilization since roots will be compromised and may be difficult to work granules into soil Reduce irrigation run times to avoid runoff irrigate in segments that let soil dry out to avoid runoff 61

Why Do We Aerate? Compacted soils Improves roots (increases air) Do Florida soils get compacted?

Warm Season Grass Growth Curve

Temperature Extremes Warm season grasses inherently designed to grow in hot, high light conditions They have temporary cessations of growth when temperatures drop and/or daylength shortens Time agronomic programs to complement this basic biology, not attempt to offset it 64

What Is This Stress? 65

The New Urban Soils Retention pond soils typically very high ph 8 or higher Become very compacted impedes root growth 66

Dealing With High ph 67

Dealing With High ph Micronutrients iron, manganese not available Phosphorous may also be limiting Micronutrient deficiencies cause interveinal chlorosis 68

Compacted Soils Lack of oxygen for roots Roots can t grow Water, other inputs can t penetrate Can form solid hardpan layer Dries out Low microbial activity 71

Why Do We Aerate? Compacted soils Improves roots (increases air) Do Florida soils get compacted?

What Is This Stress? 74

The Burning Question About Dogs and Grass 75

The Burning Question About Dogs and Grass High salts and N produce burned grass in areas where urine is concentrated How to repair? Water in with hose if possible Encourage dogs to have specific area to use Replace damaged areas with stolons or plugs No soil amendments that are effective Not related to dog s diet

What Are the Brown Spots in My Lawn? Is there evidence of a pattern from a spreader, mower, sprayer, irrigation head? Look for mechanical injury or applicator error Look at site conditions (shade, compacted soils, wet soils) 77

What Are the Brown Spots in My Lawn? Is the injury random in shape and size or does it recur in multiple locations? Check for insects Look at roots are they black, rotting (fungal disease)or truncated (soil born insect or nematodes) Does shoot system have evidence of chewing on leaves (insects) or rotting (fungal disease) Is shoot system dried out and chlorotic or necrotic? 78

Thank you for your attention! letr@ufl.edu 79