Pesticide-Free Lawn Care Tony Koski Extension Turf Specialist Colorado State University http://csuturf.colostate.edu
From the U. Minnesota web site on sustainable lawn management: Sustainable (lawn): A lawn area requiring few outside inputs (e.g., water, fertilizer) to maintain healthy grass while having a positive impact on the environment (e.g., preventing soil erosion). homeowners, business owners and related industry personnel will be able to create outdoor spaces that are functional, maintainable, environmentally sound, cost effective and aesthetically pleasing. http://www.sustland.umn.edu/
Reasons for Weed Problems in Lawns Poor cultural practices Improper species or cultivar selection Planting poor quality seed or sod The turf is placed in a situation where it can not be competitive.
Proper Mowing Height Home lawn grasses 2-3½ inches Bermudagrass and zoysiagrass lawns ¾-1½ inches Golf greens 1/10-3/16 inch Golf tees & fairways ¼ - ¾ inch
Mowing Effects on Root Growth Lower mowing heights remove more photosynthetic tissue Lower mowing heights require more frequent mowing Lower mowing heights reduce root depth and health
Proper Mowing Frequency Proper frequency is described by the 1/3 rule Never remove more than 1/3 of the turf s height at any single mowing
Reel Mowers for the Home Lawn Quiet Good quality of cut No engine maintenance Can stripe the lawn Can t mow much higher than 2 ½ inches MUST mow frequently! Difficult to use on lumpy lawns Maintenance may be a problem for the homeowner Not an effective tree leaf mulcher
Benefits of Grass Clipping Recycling Return nutrients Return organic matter Reduce load on landfills May reduce severity of certain diseases Returns pesticides to turf system
Home Lawn Fertilization Nitrogen (the first number) is most important Phosphorus, potassium, other nutrients are a bonus Grass clipping recycling will supply substantial N, and adequate amounts of other nutrients Turf species and amount of use are important considerations The older the lawn, the less often it needs fertilizer
Weed or fertilizer?
Easy Lawn Watering Apply as much water as possible, without causing runoff or deep percolation (0.5-1 ) Don t water again until you see signs of wilt or drought stress on the lawn Apply 0.5-1 inch of water again Water between 9PM and 9AM, if possible Check distribution pattern if specific dry spots persist
The most efficient time to irrigate is when there is dew/guttation fluid on the grass. Otherwise, 9pm to 9am or what local rules allow/dictate.
Natural/Organic Weed Control Corn gluten meal Preemergent herbicide activity Excellent N source ~ 1.00/pound Use rate 15-20 pounds/1000 sq. ft.
Corn Gluten Meal for Weed Control High use rates (12-20 lb/1000 ft2) One to two applications/yr Expensive - $25-$45 per application/1000 ft2 Pre-emergence only Weeds controlled: crabgrass, dandelion, plantain Overseeding limitations Fertility effect 20 lbs. CGM/1000 equals 2 lbs. N
Sclerotinia minorfor Weed Control Fungal pathogen Can provide broadleaf weed control Efficacy similar to 2,4-D But it is an important lettuce pathogen (cause of lettuce drop )
Postemergence Herbicides Burnout Weed & Grass Killer Clove Oil (12%) and sodium laurel sulphate (8%) are the active ingredients Inerts: Vinegar, Lecithin, Water, Citric acid, Mineral Oil 80% Made of special blend of vinegar and lemon juices Wilting w/in 20 minutes, dead plants by morning But are they REALLY dead?
Postemergence Herbicides Bioganic Weed & Grass Killer Active Ingredients Eugenol 2% 2-pheneythyl-propionate 2% Corn gluten meal 2% EPA: 25(b) product Not registered in AZ, CO, IN, NE, NM, ND, WA, WI
Non-selective, contact Scythe Herbicide (Dow Agrosciences) AI: Pelargonic & other fatty acids Rapid membrane destruction Effective but not selective Signal Word: Warning
Biological Management of Insect Pests Entomopathogenic Nematodes Form associations with bacteria Larvae and bacteria work together to kill the insect Quick; typically within 48 hours New juvenile nematodes are released from insect cadaver to seek new hosts
CSU Turf Program Web Site http://csuturf.colostate.edu http://www.ext.colostate.edu