How long you should water your lawn will depend on a variety of factors. Growth stage, turf type, time of year, rainfall, and watering schedule will all change the answer to this question. Below you will learn about each factor that influences how long you should water your lawn and in what way as well as signs your lawn is currently over, or under, watered.
How Long Should You Water Your Lawn For? (Generally Speaking)
In general, I advise anyone that wants a resilient lawn with a deep root system to water their lawn deeply for up to 45 minutes just once a week once their lawn is established. If you have a new lawn or if you have recently re-seeded your lawn, you should water your lawn for about 15 minutes a day.
Factors That Influence the Amount of Water Your Lawn Needs
The amount of water your lawn needs or, rather, the amount of water you will need to use to get your lawn the water it needs will vary depending on the following 7 factors.
Rainfall
Rainfall is the biggest influence on how long to water grass. One thunderstorm, for example, may be all the water your lawn needs for a week if day-to-day temperatures are cool or the days are typically overcast. A good rule to follow is that if it has rained for more than 15 minutes in the last 2 days, you can skip watering your lawn, even in hot weather.
The average lawn, with good drainage and healthy grass, only needs about 1.5 inches of water or rain per week. You can get this from 15 to 20 minutes of hard rain or about 45 minutes of running your sprinklers just before sunrise.
Temperature
The warmer the weather and the more sunlight your lawn gets, the greater the rate of evaporation will be. For your lawn to get the water it needs, you should water it during the coolest, shadiest parts of the day to cut down on evaporation. Further, your lawn may need more water in hotter weather.
If you follow my general recommendation and water your lawn for about 45 minutes once a week in the hour before sunrise, or for 15 minutes every other day in that same time slot, you should still occasionally check your lawn for signs of dryness.
If temperatures exceed 85F on average for more than 4 hours per day, your lawn may still become dry or damaged. In cases like this, I would water your lawn for an additional 2 to 5 minutes in the late afternoon, just after the hottest part of the day.
Humidity
In general, the warmer the air is, the higher the relative humidity will be unless you live in a region with little natural water or greenery. If this is the case, you may need to increase the amount of water you use to water your lawn and the length of time you need to water your lawn.
As mentioned above, the more natural water your lawn gets, from rain or other sources, the less you need to water it. The same is true of humid weather. When humidity is over 75%, less water will evaporate. This may lead to more water being retained in the soil. If the soil is still wet when you go out to water your lawn, consider waiting or skipping a watering session.
On the other side of this issue, you have low humidity. If the average temperature is over 60F and relative humidity is under 30%, your lawn may dry out faster than usual. In this case, consider watering your lawn more frequently (splitting the average 45 minutes once a week into 15 minutes every other day) or adding another watering session in the late afternoon for a few minutes if your lawn is exhibiting signs of excessive dryness.
Time of Day
Most lawns will start and end the day looking more vibrant and hydrated than they will look during the hottest part of the day. This does not mean you should water your lawn during this time. If you water your lawn in the morning or evening, before the sun comes up or after the sun has gone down, your grass will devote more energy to absorbing water and have to fight for it less.
While it’s dark, your grass isn’t devoting as much energy to photosynthesis and will store resources more efficiently. Further, the darkness means that less water will be lost to evaporation.
Soil Type
Different types of soil will retain water better than others. While “well-draining” soil will help keep your lawn healthy by preventing overwatering or standing water from leading to disease, it also means some of the water you add to your lawn is being lost. This is why watering your lawn slowly over the course of 45 minutes on a fine spray is much better than drenching your lawn with soaker-style irrigation for 5 minutes.
Sandy soils lose the most water and clay soils retain the most. Ideally, you will have a mix of these or a loamy soil type that retains just the right amount of water. Sand and clay can also be used to amend soil over time if you have long-term drainage or water retention issues.
Grass Growth Stage
New grass will need more water than established grass. If your lawn is recently sprouted or has only been mown once, it should be watered every other day until it has been trained to follow a deep watering schedule. This will help it establish more quickly and evenly.
Grass Type
Grass type is the last factor that determines how long you should water your lawn. For example, grass types with no rhizomes and shallow roots will need more frequent watering for a shorter duration while grass types with rhizomes or deep root systems do best with deep watering done just once a week. If your grass has short roots but should have a deep root system, this watering style can also help cure your lawn of shallow roots.
Signs You’re Not Watering Your Lawn Enough
There are 4 main signs that your lawn isn’t getting enough water. If you notice any of these signs, you should know how long to run your sprinklers for another session. For example, if you see more than one of the following signs, it’s a good idea to go ahead and give your lawn 2 to 5 extra minutes of water or about 1/4” to 1/2”.
- Brittle, Dry Grass – If your grass seems unusually thin or dry and brittle to the touch, it may not have enough water. It’s normal for blades of grass to feel this way in the middle of the afternoon during a heatwave, however, only add extra water in this case if you also notice one of the other signs.
- Changes in Color – Grass without enough water will appear dull, even gray or brown, when dehydrated.
- Burnt Tips – Grass that hasn’t had enough water may eventually develop dry, brown, burnt-looking ends.
- Dusty Grass – One of the signs of dry soil, something that will lead to a dehydrated lawn, is an overabundance of dust. If it seems like you kick up a cloud of dust from just walking across your lawn, it may need more water.
Signs You’re Watering Your Lawn for Too Long
Overwatering your lawn can cause just as much if not more lasting damage than having a dry lawn. Below are the signs you should watch out for.
- Standing Water or Puddles – Puddles are the easiest sign of an overwatered lawn to spot. If there are any puddles or standing water, refrain from adding more. Dew on grass does not count as standing water.
- Soft or Squishy Blades of Grass – If your grass has become too wet for too long, it may attract bacteria that will cause it to rot or seem as if it’s rotting. If you can easily squish the blades of grass with your fingers and they seem to deteriorate, your lawn may be habitually overwatered.
- Changes in Color (Darkening) – If your lawn appears darker than usual or if patches of it are so green they’re almost black, your lawn may be overwatered.
- Mushroom, Mold, or Algae Growth – If you notice large numbers of mushrooms, mold, or algae on your lawn, your lawn may be overwatered.
- Limp or Rotting Roots – Lawns that are chronically overwatered are susceptible to root rot.
- Frogs, Slugs, and Snails – When moisture is constantly present on your lawn, it attracts frogs, snails, and slugs.
- Your Lawn Isn’t Dry By 3pm – The easiest way to know if your lawn is getting too much moisture is to feel the grass at 3 PM. If it’s wet and you water it at the recommended time, about 5 AM, then you should skip your next scheduled watering.
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