Watering Your Lawn – How and When


It is a common misconception that as long as you water your lawn, it will thrive.  This is only true in its most basic sense in that you do have to make sure your lawn gets water.  Several factors determine the correct manner of do.

Remember, your lawn is alive.  The soil needs a proper environment to deliver the right nutrients to the roots that give life to your grass. How long you water your lawn, the frequency at which you water, and the when you water are all important.

Keep reading for all of the factors you need to consider before heading outside and turning on the spigot. 

A sprinkler system performing its lawn care at its scheduled sprinkler times

Different Types of Water Delivery Systems

Not all irrigation systems are created equally.  Below is a basic explanation of the primary ways of watering your lawn.

In-Ground or Pop Up Irrigation System

  • The most consistent way to provide your lawn the water it needs
  • Turns on at preset times
  • Delivers a precise amount of water before automatically shutting off

Oscillating Sprinkler System

  • Sprays vertically and moves back and forth over a specific area of your yard
  • Susceptible to both interference from the wind and evaporation

Pulsating or Rotating Sprinkler System

  • Sprays out horizontally at a high velocity
  • Less susceptible to wind interference and evaporation
  • Preferable to oscillating sprinklers
A man holding a garden hose to water his lawn

Watering By Hand

  • Use of sprayer attachments on the garden hose for different types of coverage
  • Beneficial in that you can physically see how much water you are putting into each area

How Often Should You Water Your Lawn

Determining the frequency with which you should water your property depends on a few different factors.

The first consideration is the type of grass you have in your lawn.  Generally speaking, cool-season grasses such as Kentucky bluegrass or perennial ryegrass require more water than warm-season grasses like St. Augustine or Bermuda grass.  A good rule of thumb is to water cool-season grasses every 2 to 3 days and every 3 to 4 days for the warm season grasses during the growing season.

Newly seeded lawns need to be watered more often unless there is sufficient rainfall to meet your lawn’s water requirements.  Be careful not to overwater, though, as this will wash away the grass seed before it has the chance to take root.

An oscillating sprinkler system attached to a green garden hose

In the colder parts of the year, watering your lawn is entirely dependent on the type of winter weather you experience.  In the parts of the country where snow and frost are a constant, you can hang up the irrigation equipment until the thaw of spring.

In milder climates where some freezing temperatures occur with the occasional warmer day, the sporadic rain and snow should provide a sufficient amount of moisture to sustain your lawn.

How do you know if your lawn can handle watering in the winter months?  Remember this phrase, “If you’re still mowing, your lawn is growing.”  If this is true for your lawn, it needs to be watered on the schedule mentioned above until it stops growing.

How Long Should You Water Your Lawn

Your lawn needs between 1-1.5 inches of water per week to maintain ideal soil conditions. You want to water deeply during the watering cycle. Generally speaking, watering your lawn for 20 minutes to 30 minutes long, three times per week will provide an adequate amount of water for your yard.  You do not want to water every day. There are a couple of ways to ascertain the amount of water your grass is receiving every time it is watered.

Flow Timer or Water Timer

These timers measure water flow in the total number of gallons of water your lawn is receiving.  The formula for determining how many gallons of water you need to provide your lawn with 1 inch of water is a relatively simple calculation.  Take the total square footage of your lawn and multiply it by .62 gallons.  The number you get will give you the total number of gallons to cover your lawn with one inch of water.

If you are watering your lawn more than one time a week, divide that number of gallons by the number of days you plan to water and you will have the correct amount of gallons for each time you plan to water your grass.  Program your timer to shut off at the desired number of gallons and you’re done.  These are ideal for in-ground irrigation systems.

A simple sprinkler spraying water up into the air

Tuna Can Method

Measure the depth of the water each area of your lawn is receiving by placing an empty tuna can flat onto the ground in an area you will be watering.  All you have to do is water your lawn until the water rises to a specified depth in the tuna can.  The number of days you plan on watering your lawn will determine the necessary height of the water in the tuna can.

The corresponding depths follow here:

  • Every 4 days – ½” to ¾”
  • Every 3 days – ⅓” to ½”
  • Every 2 days – ¼” to ⅜”

Once you have determined how long it takes to fill your tuna can to your desired height, you can set your sprinkler time to always stay on for that long when you water the lawn. This way, your sprinkler will always be on for as long as it should be on. 

Screwdriver Method

Another way to tell if your lawn is receiving enough water is to take a standard screwdriver and push it into the soil.  If you can depress it to the handle of the screwdriver, you are not under watering your lawn.

wet blades of grass

Best Time to Water Your Lawn

Ideally, the best time to water the lawn is between sometime in the early morning to before 10 a.m.  This will keep the earth cooler during the hottest parts of the day and allow ample time for the grass to dry before nightfall.

If this is not practical, late afternoon is still an acceptable time to perform lawn watering.  Because the sun is still out, the grass still has the opportunity to evaporate from the blades and absorb into the soil.  However, watering this late should be avoided if possible.

Avoid watering into the evening entirely.  Watering once the sun is going down will keep your lawn wet through the night and more prone to disease and fungus growth.

What Happens If There Is Not Enough Water On Your Lawn

An insufficient amount of water will cause your lawn to discolor and will also dry out the soil.

Lack of water can lead to the presence of the heat and stress fungus ascochyta leaf blight (also called the dollar spot fungus).  This fungus is characterized by a yellowing in the middle of the grass blades.

The soil is alive, too, and also needs water to survive.  When it is under-watered, it can lead to insufficient amounts of beneficial microbial activity. These microbes, which provide nutrients to the roots, need moisture to sustain themselves.

Often, your lawn will go dormant if it does not receive enough water.  When your lawn goes dormant, it begins to discolor, and it ceases to grow.  This can happen if you neglect to water your yard in the hot summer months during a drought.

Drops of water are being sprayed over a lawn for proper lawn care

What Happens If There Is Too Much Water On Your Lawn

Too much water on your lawn can drown your grass’ root system because it needs air to survive.  Porous soil has pockets of air that aid in the circulation of the oxygen and nutrients vital for the growth and strength of the roots.

On newer lawns, too much water will keep the roots shallow because they do not have to grow deeper into the ground to find their water source.  Shallow roots make for grass that is not as viable and more prone to disease and fungus growth.

Furthermore, over-watered lawns will result in an excessive amount of weed, like crabgrass or nutsedge.  Patches of thick thatch will appear on different areas of your lawn’s surface.  There will also be more insect activity on your lawn because they use it as a water source.

4 different sprinklers going off at the same time.

Overwatering will also necessitate more fertilization because it will push the fertilizer through the grass’s root zone.  When the fertilizer goes beyond the root system, ground pollution occurs in the form of nitrogen run-off.

Last but not least, you will see an unnecessary increase in your energy bills because you have given your lawn more water than it needed to thrive.

With these tips, you will have luscious and healthy grass in no time

Happy Planting!

About the author: Carley Miller is a horticultural expert at TheGreenPinky. She previously owned a landscaping business for 25 years and worked at a local garden center for 10 years. Read More

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