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Lawn Care Guidelines

A healthy lawn requires proper attention to three important areas:

WATERING - Improper watering is a significant cause of damaged lawns

FERTILIZATION - Proper fertilization will lead to a healthy, lush lawn and result in less damage from weeds and disease

MOWING - A sharp-bladed mower can have a lawn looking well-clipped and tidy


  • Irrigate long enough for the water to reach at least six inches in depth so roots will not be shallow.

  • Shallow roots are less able to tolerate changes in temperature and soil moisture.

  • Examine the soil with a shovel or probe several hours after watering to determine how deeply the water infiltrated the root zone.  Water as needed to maintain a moist root zone.


When to Water:

  • Early morning is the best time to water to improve irrigation efficiency and limit disease.

  • There is less hot weather in the morning and a full day to dry the leaves.

  • Night watering can lead to disease from the leaves being wet for too long.

Improve Watering Effectiveness:

  • Make all the water available to the grass.

  • Grass with accumulated thatch and/or compacted soil cannot absorb water easily.



  • Leaches nutrients, especially nitrogen.

  • Encourages weeds.

  • Causes oxygen depletion in the root zone.



  • Adequate amounts of nitrogen, phosphorus, and potassium are essential.

  • Grasses are heavy users of nitrogen and potassium.

  • Potassium should be applied in equal ratios with nitrogen especially if lawns clippings are removed.


When to Fertilize:

  • An easy way to remember is to fertilize near the holidays of Easter, Memorial Day, 4th of July, Labor Day, and Halloween.

  • Mulch mowing is equivalent to one or two fertilizer applications.


How Much Fertilizer:

  • 4 lbs. of nitrogen per 1,000 square feet per year whether a complete fertilizer or only nitrogen.

  • Divide the amount into 4 or 5 equal applications to provide the season total.



  • Enhances color and helps limit certain weeds and diseases.

  • Recommend 2 to 3 lbs. per 1,000 square feet per year applied over two applications.

  • Either select a lawn fertilizer that contains sulfur or apply ammonium sulfate.



  • Dull mowers cause chewed-off, ragged grass blades to die back and give the lawn an off-color appearance.


Grass Height:

  • Set the mower at 1.5 to 2 inches for fine-leafed fescues.  Closer mowing will weaken fescue.

  • Kentucky Bluegrass (including any seed mixes with the bluegrass) should be mowed at 2 to 2.5 inches.

  • Mowing at taller heights help shade the soil and cool the root system which improves heat and drought tolerance, and results in less water use.

  • Taller grass reduces weed seed germination because light is prevented from penetrating the soil.


Grass Clippings:

  • Leave grass clippings on the lawn as you mow.

  • Clippings break down quickly, add nitrogen, and contrary to common belief, don't add to thatch buildup.

  • Nutrient deficiencies occur more readily when all clippings are removed.

  • Clippings are equivalent to one to two fertilizer applications.

  • Clippings on the lawn save landfill space.

  • Excessive clippings should be removed to prevent smothering, disease, and for improved appearance.




  • Thatch is the dead, matted layer of stems and roots above the surface of the soil where water is trapped and evaporates instead of reaching the root zone.  

  • If there is more than 1/2 inch of thatch remove the excess.  

  • Thatch can best be removed by using a dethatcher from a rental company or attachments for your lawn mower.



  • A hard, compacted lawn needs aerating to open the soil and allow for better water and air penetration down into the root zone.  

  • Smaller areas can be spiked with a pitchfork or other manual devices, while power aerifier machines are best for larger lawns.  

  • For improved penetration, make sure the soil is moist when aerating.

The above Columbia Basin Conservation District information is courtesy of WSU Extension. Their lawn publication materials can be found online.

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