Dr. Tony Koski
Extension Turf Specialist
Colorado State University Cooperative Extension
Fort Collins, CO

Current landscape watering restrictions can vary considerably from one city to the next, but most cities are allowing, at a minimum, twice-weekly lawn watering. Twice-weekly watering was sufficient to maintain green turf during the March-June period, but a return to normal summer temperatures and precipitation will cause moderate to severe lawn stress - especially under the most restrictive (twice-weekly watering, with time limitations of 15-20 minutes/station) scenarios. The following lawn care suggestions will help your lawn survive a summer with watering restrictions, until cooler temperatures return in the fall.

For those homeowners managing lawns without watering restrictions, please refer to the CSU Cooperative Extension basic lawn care fact sheet (Lawn Care 7.202). Water responsibly, even if you are not living with landscape watering restrictions! Your lawn and other landscape plants will be healthier if you water efficiently.

Fertilizing the Lawn

• Fertilization may not be necessary if the lawn was fertilized this spring
  
• Summer fertilization, if done, should utilize a blend of slowly available (highest percentage) and quickly available nitrogen (low percentage)
  
  • Most lawn care companies use these type of fertilizer blends
  • Excellent fertilizer blends are available to the homeowner from local nurseries and garden centers
• Natural organic and other predominately slowly available nitrogen fertilizers work well when applied in the summer
  
• Coordinate any fertilizer applications with your local watering schedule so that it can be watered in as soon as possible after application
  
• Returning grass clippings to the lawn when mowing provides a substantial fertilizer benefit

Aerating (Cultivating) the Lawn

• Unless used for overseeding purposes, lawn aeration should not be performed when temperatures are expected to exceed 85F for more than a couple of days
  
• Watering restrictions may cause lawns to be too hard to allow for effective summer aeration
  
• Lawns aerated during the summer may require additional irrigation to prevent turf stress and damage
  
• Fall (September-November) aeration can be scheduled at this time, perhaps to include overseeding for those lawns that have been thinned by drought and watering restrictions
  
• Fall lawn aeration is important for controlling thatch, an organic layer that often impedes proper water movement into the soil
  
• Fall lawn aeration, fertilization, and overseeding all can be done at the same time

Mowing the Lawn

• Set your mowing height at 2 ½ to 3 inches and mow at the same height all growing season
  
• Don't remove more than 3/4 inch of grass at any single mowing; recycle grass clippings into the lawn
  
• Use a sharp blade to reduce tearing of the grass leaves
  
• Whenever possible, mow during the cooler morning or evening hours to avoid causing stress to the lawn
  
• Lawns showing signs of drought stress (blue-gray coloration, persistent footprints, slight browning) should not be mowed until they have been watered to reduce stress; mow during the cool hours of the day

Weed Control in the Lawn

• Drought-stressed, thin lawns are susceptible to invasion by a number of lawn weeds, including: dandelion, bindweed, spurge, mallow, crabgrass, and foxtail
  
• Weeds (especially crabgrass and spurge) will be more common on those areas of the lawn where irrigation coverage is less than optimal, as well as along sidewalks and driveways
  
• Drought-stressed weeds can be difficult to kill with summer herbicide applications
  
• Weeds should be green and growing when herbicides are applied
  
• Whenever possible and practical, weeds should be spot-treated
  
• Weeds not controlled with summer herbicide applications are more easily controlled with fall treatments
  
• Herbicides should not be applied under windy conditions, and when temperatures exceed 85-90 F

Watering the Lawn

• Follow watering programs encouraged or mandated in your community
  
• Water the lawn whenever it is allowed
  
• Disregard for required community watering practices can result in substantial fines and may encourage communities to enact even stricter watering restrictions
  
• Contact your local water utility for information on your local watering restrictions; watering restriction information can also be found HERE
  
• Effective lawn irrigation requires an understanding of how the irrigation system operates, as well as ongoing maintenance of sprinkler heads
  
• Learn how to program your control clock so that you irrigate according to the schedule mandated for your community
  
• Set the clock so that irrigation occurs between 6PM and 10 AM (or as otherwise mandated)
  
• Repair or replace broken irrigation heads
  
• Adjust irrigation heads to avoid throwing water on streets, driveways, and other hardscapes
  
• If you find that adjusting or repairing your irrigation system is too time-consuming or challenging, hire an irrigation or landscape management specialist to perform this important work
  
• Your lawn care company professional may be willing to program your irrigation control clock for you
  
• Contact your local water provider for information on conducting an irrigation audit; some lawn care companies, landscape management firms, or irrigation installation firms will conduct an audit of your irrigation system for a modest fee
  
• Even with unlimited watering per irrigation zone on a twice-weekly basis, lawns often will show signs of stress
  
• Summer root stress reduces the ability of root systems to use water
  
• Stress will first appear in areas where irrigation coverage is lacking

Other Lawn Care Practices

• The application of wetting agents specifically developed for use on turf is recommended to reduce the occurrence of water repellent conditions in lawns
  
• Wetting agents can benefit lawns subjected to extreme drying over the past few months by promoting better infiltration of water into the soil; summer use may reduce the occurrence and/or severity of dry spots in the lawn (but will NOT totally compensate for poor irrigation coverage)
  
• Wetting agents are available in both granular and liquid forms; granular formulations are often easier for homeowners to apply
  
• The use of dishwashing detergents and other soaps in place of turf-type wetting agents is not recommended and may damage heat- and drought-stressed lawns
  
• The incorporation of water-absorbing polymers (sometimes called "hydrogels") into new or existing lawns does NOT reduce lawn water requirements and is not recommended for Colorado lawns
  
• The application of green colorants to dormant lawns is safe, provided that paints or colorants developed for turf are used; professional application by a lawn care or landscape management company is recommended

Brown Spots in the Water-Restricted Lawn

• With the exception of billbug and white grub injury, brown spots in the Colorado lawn are rarely caused by insects; routine insecticide applications (encouraged on television advertisements by some lawn product companies) are highly discouraged and will do nothing to improve the quality of a drought-stressed lawn
  
• Billbugs can injure lawns during the summer months (June-August)
  
• White grubs may injure lawns during the late summer/early fall
  
• It is important to properly ID lawn insects prior to making any insecticide application
  
• Ascochyta leaf blight is a common and important disease on drought-stressed turf, often causing extensive browning of lawns

Information contained in this fact sheet is intended for use from July 1-September 30, 2003. New information on fall/winter lawn care will be posted in September.

This information may be printed/disseminated IN ITS ENTIRETY. Please print and photocopy the PDF version. University regulations prohibit the addition of company or municipal logos.

Read and abide by all instructions before using any pesticide, fertilizer, or other turf care product. The use of products not labeled for or intended for use on lawns may damage turf, especially when lawns are under heat and drought stress.

Written June 2003