When and How to Water Your Lawn

Irrigating your lawn isn’t as simple as “just add water.” You have to make sure your grass gets enough water, but not too much. You have to water at the right time and make sure the water is distributed evenly throughout the whole lawn. This lawn watering guide explains how to do all of that, with details on when and how to water your lawn.

When to water the lawn 

Instead of watering your lawn according to the calendar, it’s best to keep an eye on the grass and only water when it shows signs of drought stress.

Some signs to look for:

• Fading color: Your grass turns a dull green or grayish color.
• Footprints: When you walk across the lawn, your footprints remain visible, meaning your grass doesn’t have enough moisture to bounce back.
• Curling grass blades: The individual grass blades curl in or roll in on themselves.

These signs are nature’s hint that it’s time to water your lawn. You might notice them after one or two weeks without water or longer depending on your grass type. As soon as your grass gets the drink it’s been hankering for, it will return to normal.

Best time of day to water the lawn 

Always water your lawn in the early morning, between 4 a.m. and 10 a.m. In the morning, temperatures are still cool, and your grass will have time to absorb the water before it evaporates under the hot sun of midday.

Don’t water your lawn at night or in the evening. After dark, the water would sit in the grass for too long, potentially causing lawn diseases and attracting pests.

How much to water the lawn

When it’s time to water the lawn, about 1-1½ inches of water per square foot should do the trick. That’s enough to moisten the soil down to 6-8 inches deep, depending on your soil type. The 1-1½ inches includes rainfall, so there’s usually no need to irrigate during your area’s rainy season (if you have one).

Deep, infrequent watering is better for your lawn than frequent, shallow watering. Infrequent watering encourages a deeper root system, which improves drought tolerance and makes the grass stronger overall.

How long to water the lawn with sprinklers

If you’re using sprinklers, you need to figure out how long you have to run them for each square foot of your lawn to receive at least an inch of water. There are a few ways to calculate this.

Method 1: Use your sprinkler system’s flow rate

1. Multiply the square footage of your lawn by 0.62 gallons (equivalent to 1 inch of water per square foot) to figure out how much water it takes to cover your whole lawn.
2. Find out the flow rate of your sprinkler heads, measured in gallons per minute. You should be able to find this information in the owner’s manual or on the manufacturer’s website.
3. Multiply the flow rate by the number of sprinkler heads in your lawn.
4. Take the answer to Step 1 (the amount of water in gallons it takes to cover your lawn) and divide it by the answer to Step 3 (the flow rate of your sprinkler system as a whole measured in gallons per minute).
5. The answer to that division tells you how many minutes to run your sprinklers when your grass shows signs of drought stress.

Example:

1. 10,000 square feet of lawn x 0.62 gallons = 6,200 gallons of water total

2. Flow rate of 7 gallons per minute for each sprinkler head 

3. 7 gallons per minute x 20 sprinkler heads = 140 gallons per minute total

4. 6,200 gallons of water ÷ 140 gallons per minute = about 44 minutes

5. So, when this example lawn shows signs of drought stress, the homeowner should run their sprinklers for about 44 minutes. 

Method 2: Measure with cans 

1. Place empty, shallow cans (such as tuna cans or cat food cans) around your lawn.
2. Turn on your sprinklers.
3. Keep track of how long it takes for the sprinklers to fill the cans (should be about 1-1½ inches of water in each).
4. If the timing is different for cans in different areas of the lawn, average all the times together. That average is about how long you should run your lawn sprinklers.

If you notice water pooling on the lawn after running the sprinklers, water in increments instead of all at once. Run the sprinklers for 10 minutes, then give that water 10 minutes to seep into the soil. Continue this 10 minutes on/10 minutes off pattern until you’ve run the sprinklers for the total amount of time needed.

Water your lawn uniformly 

Where the water goes is just as important as how much of it you use. Without uniform watering across the whole lawn, you’ll end up with some sections of grass that get too much water and some that don’t get enough. The result is a patchy, unhealthy lawn (not to mention wasted water).

When watering the lawn by hand with a sprayer: Walk slowly across the lawn to ensure you don’t miss any spots. Pay close attention to the range of your sprayer so you don’t overlap on certain sections of the lawn.

Inspect each section of grass before you continue spraying. If it’s already wet, move on to the next section.

When watering the lawn with a movable sprinkler: Use one of the methods described above to figure out how long you need to run the sprinkler in each section of your lawn.

If using the flow rate method, plug in the sprinkler’s range in square feet rather than the square footage of your whole lawn. Notice where the sprinkler’s range cuts off so when you move it to the next part of your lawn, there are no spots missed and no overlap.

When watering the lawn with a sprinkler system: Each spring, when you start your sprinklers back up after winter, check to make sure that they’re covering your lawn evenly. You can test this with cans:

1. Set up shallow cans (tuna cans, cat food cans, etc) at regular increments in a grid pattern across your lawn.
2. Run the sprinklers for 15 minutes.
3. After running the sprinklers, each can should have about the same amount of water in it. If any of the cans have less than the others, that section of your lawn may not be getting enough water.

In the event of uneven coverage, the cause could be improper installation, a damaged sprinkler head, or another problem with the system. Call a pro for an irrigation audit and any necessary repairs.

Dangers of overwatering the lawn

Don’t be afraid to let your lawn get a little thirsty in between watering sessions. In most cases, underwatering is better than overwatering. When you water the lawn too much or too often, the grass stays wet, which is bad for several reasons.

Some common lawn problems caused by constantly wet grass:

• Fungal lawn diseases such as brown patch, leaf spot, or powdery mildew
• Infestations of lawn pests
• More weeds
• Weak grassroots
• Lack of oxygen in the soil, which prevents your grass from absorbing essential nutrients
• Soil erosion

Drought stress caused by underwatering is a quick fix: As soon as you water the grass, it will be as good as new. But these problems caused by overwatering could take years to reverse, or they could kill your grass completely.

Another big issue with overwatering is all the waste it causes – wasted money on your water bill and wasted water resources that could be put to better use. The EPA estimates that about 50% of the water used for irrigation in the United States goes to waste. Odds are, you can water your grass a lot less than you do now and still have a healthy lawn.

Water needs for different lawns 

The guidelines described above are generally effective, but every lawn is different. Your lawn’s perfect watering schedule ultimately depends on your grass type, the type of soil in your yard, and the local weather. Now, we’ll get into some watering advice for different lawns.

Watering cool-season vs. warm-season grasses 

Many different species of grass are used for lawns across the United States. They all fall into one of two categories:

• Cool-season grasses grow in the northern portion of the country. They grow most actively in the cooler weather of spring and fall and go dormant in summer. Water these grass types regularly in spring and fall and less often in summer and winter.
• Warm-season grasses grow in the southern portion of the country. They grow most actively in the hot weather of late spring and summer. Water these grass types regularly in spring and summer, then slow down in fall.

Cool-season grasses typically perform poorly in heat and drought and need about 36% more water than warm-season grasses. Cool-season grasses may use even more than that during summer when the heat evaporates more water and the grass suffers from heat stress.

If you live in the transition zone where both grass types grow, you could save water by choosing a warm-season type.

Watering different soil types

Your soil type affects how often you need to water your lawn.

Sandy soils: Water leaches quickly out of loose, sandy soils, so you’ll need to water the lawn more frequently if your soil contains a lot of sand.

Clay soils: Compacted clay soils, on the other hand, retain water for a long time. Water a lawn growing in mostly clay soil too frequently, and you’ll end up with a waterlogged lawn.

Loam and silt soils: Loam and silt fall somewhere in the middle when it comes to water drainage. They can retain water, but they have better filtration than clay.

Watering new lawns

Newly seeded or sodded lawns use a lot more water than established lawns. Their fledgling roots need all the help they can get to anchor into your soil.

For new grass seeds: Keep the top inch of soil moist until the seeds germinate. Once they germinate, keep the top 2 inches of soil moist until the grass reaches a height of about 3 inches.

During this time while your grass is establishing itself, you’ll probably have to water once and maybe even twice per day. Once it reaches its mature height, you can gradually transition to watering once per week or when signs of drought stress appear.

For new sod: Sod also needs consistently moist soil to establish its roots. You should keep the top 3-4 inches of soil moist for about two months after installation. You’ll probably need to water twice a day for about 20 – 30 minutes each session. After two months, you can transition to a normal watering schedule.

Drought-tolerant grass types 

Some grass species use less water than others. There are even cultivars of grass bred specifically to tolerate drought better.

The Turfgrass Water Conservation Alliance has a list of the most drought-tolerant grass species and cultivars. The list includes:

• Bermuda cultivar “Princess 77”
• Several fine fescue cultivars
• Several Kentucky bluegrass cultivars
• Several perennial ryegrass cultivars
• Several tall fescue cultivars

If you’re looking to save water – and especially if you live in a region that suffers from drought – consider switching your lawn to one of these grass types that use the least amount of water.

Choosing the right irrigation system

Another aspect of proper lawn watering practices is making sure you have the best sprinkler system for your yard. Using the right sprinklers will ensure even coverage and help you waste less water.

Different types of sprinklers include:

• Above-ground sprinklers: Movable, easy-to-install sprinklers that attach to your garden hose
• In-ground sprinklers: Sprinklers with pipes installed underground
• Oscillating sprinklers: Made up of a metal or plastic tube with several small holes in it for thin streams of water that sweep back and forth across the lawn (the kind you ran through as a kid during summer)
• Stationary sprinklers: Sprinklers that spray water in a pre-set square, rectangular, or circular pattern over a small area
• Traveling sprinklers: A Roomba-esque sprinkler that scoots around your lawn on wheels, propelled by water pressure
• Rotor sprinklers: Sprinklers that spray water in a circular pattern and can reach across long distances
• Bubblers: Small waterfall-like sprinklers best for watering tree and shrub roots
• Drip irrigation: A series of tubes with holes at various intervals where water spouts out as needed; good at reducing water waste

Decide which type of sprinkler system is best for you based on your budget and the size and shape of your yard.

FAQ about watering the lawn

More lawn maintenance tips

Watering, mowing, and fertilizing are the ABCs of lawn care. Get those three things right, and you’ll have a thick, healthy lawn free of pests, diseases, and weeds.

Now that you’ve learned the best way to water your lawn, why not complete your education? Lawn Love has guides on how to mow your lawn and how to fertilize your lawn.