Winter/Spring Lawn Management Checklist for Colorado Lawns

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

Many areas of the Front Range have experienced a drier than average spring, with March and April being significantly drier than normal. Irrigation restrictions vary widely from one community to the next. The homeowner is encouraged to irrigate whenever allowed, to offset the effects of a dry winter and spring. The following lawn care recommendations apply equally to both the commercial lawn care customer and those homeowners who care for their own lawns.

Fertilizing the Lawn

• Fertilization of lawns this spring (March-June) is a highly recommended practice
• The ideal fertilizer will contain a mixture of quickly and slowly available nitrogen sources
  • Most lawn care companies use these type of fertilizer blends
  • Excellent fertilizer blends are available to the homeowner from local nurseries and garden centers
• Fertilizer applied before watering is allowed will not cause a problem for lawns; adequate moisture from spring precipitation and irrigation (once it is allowed) will cause nutrients to be released to the turf

Aerating (Cultivating) the Lawn

• Lawn aeration is a highly recommended spring lawn care practice
• While deeper (2-3 inches) core holes provide the greatest benefit to the lawn, even shallow (1 inch) core holes will help to enhance water infiltration for the spring and summer watering periods
• Overseeding may be done in conjunction with lawn aeration; this may especially benefit those lawns thinned by drought conditions or winter mite activity (avoid using crabgrass preemergent herbicides at the time of overseeding)
• Lawn aeration will help to control thatch, an organic layer that often impedes proper water movement into the soil
• 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

Weed Control in the Lawn

• The use of preemergent herbicides for prevention of crabgrass, foxtail, and other annual grassy weed problems is a recommended spring lawn care practice
  • These products should NOT be used on those lawns being overseeded in the spring
  • Any preemergent herbicide should be watered in with at least ½ inch of water as soon as possible after application
• Where a preemergent herbicide is not used in the spring for crabgrass prevention (perhaps when lawns are being overseeded), there are excellent postemergent herbicide products for the control of young annual grassy weeds
  • These products are expensive and not generally available for homeowner use
  • These crabgrass control products work most effectively when applied by lawn care professionals
• Control of dandelion, clover, bindweed and other perennial broadleaf weeds can be done in the spring
  • There are a variety of excellent products available to the homeowner at local garden centers
  • The most effective broadleaf herbicides are those used by professional lawn care companies
  • Spot treatment of individual weeds is the most effective method of controlling broadleaf weeds
  • Broadleaf weeds are most effectively controlled when daytime temperatures are in the 50s to mid 70s and soil moisture is high enough that weeds are not drought-stressed

Watering the Lawn

• Follow watering programs encouraged or mandated in your community
  • Begin irrigating the lawn as soon as it is allowed
  • The less frequent irrigation regimes allowed in some communities, especially during the spring, may actually enhance turf drought resistance for the summer
  • Where twice-weekly irrigation is allowed (especially if there are no time limitations), good lawn quality can be expected throughout the spring and summer
  • Once-weekly irrigation can produce good turf quality for most of the spring, and will be sufficient to allow most lawns to survive even a hot and dry summer
  • Disregard for required community watering practices can result in substantial fines and may encourage communities to enact even stricter watering restrictions
• As soon as irrigation is allowed in the spring, take time to refresh your understanding of how your irrigation system operates
  • 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 in your community or water district)
  • 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
• On your watering day, irrigate using the following technique (unless otherwise mandated by local regulations):
  • Apply ¾ to 1 inch of water, slowly enough that runoff and puddling do not occur
  • Cycling through irrigation stations or moving your sprinkler around the yard (applying smaller amounts of water) while irrigating helps water to soak more thoroughly and evenly into the lawn; repeat your cycle until the desired amount of water has been applied
  • Hand-watering small or isolated dry spots, where sprinklers don't overlap properly, will save water

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; spring and 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

Information contained in this fact sheet is intended for use from January 1-June 30.

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.