The best time to water your grass is early morning, preferably before 10 a.m. Watering during this time is the most efficient, letting your grass absorb as much water as possible while reducing the risk of fungal problems.
When to water your lawn can be a heated topic, and there are different schools of thought. Ideally, the goal is to water at a time during the day when your grass absorbs as much of the irrigation amount as possible while staying wet for as little time as possible.
So, let’s talk about the best time of day to water your lawn and why this timing is so important!
Why is it important to water at a specific time?
It may seem like you can turn on your sprinklers and water anytime during the day, and it’s not unusual to see commercial and residential lawns being watered at all hours. However, there is an optimal time for watering that uses water the most efficiently and is healthiest for your grass. But, that optimal time takes into account a few different factors.
First, let’s talk about water use efficiency. When watering, the goal should be to get as much of the water from the sprinklers into the ground so the grass roots can absorb it.
With this in mind, you want to water when it’s cooler and the wind is relatively calm to prevent evaporation.
In most places, the temperatures are lower through the night when the sun is down, and they climb once the sun rises. Wind speeds tend to follow a similar pattern. Winds typically calm down at night when the sun sets and then start to pick back up again as the temperature warms when the sun rises.
You want to find that sweet spot where the sun isn’t blazing, evaporating precious water droplets before they even reach the ground, and the wind isn’t whipping around, blowing water everywhere, but its intended destination.
At first, it would be easy to think, great, let’s water during the evening or through the night when it’s cool and calm. Unfortunately, there are some dangers to this.
Yes, these times are great for achieving the least amount of evaporation possible, but on the flip side, they also have a higher risk of encouraging fungal problems. Cool, damp conditions are often prime for diseases. To decrease disease pressure, you want to minimize the time your grass stays wet after watering.
Hence, you ideally want to water early in the morning or just as the sun is coming up so your grass isn’t wet overnight. If that just isn’t possible, you can water in the evening. Just make sure your grass dries before the sun sets.
Now you can see why early morning is best. However, the exact time may depend on your local community and its water use habits.
In many places, residents draw heavily on water resources in the early morning and evening hours. Peak demand is often between 7 and 10 a.m. as people get ready for school and work.
If you set your sprinklers during this heavy use period, you may see a drop in water pressure as the water source is experiencing high demand. Since you don’t want your sprinklers running inefficiently, you may need to set them to run earlier so they are finishing watering as the sun comes up and households get busy.
Are there any special considerations for when to water your grass?
In general, you always want to avoid watering during the hottest part of the day and should try to water your lawn early in the morning. But this recommendation doesn’t fully apply if you’re watering new sod or grass seed.
With new sod or seed, you need to water your grass often through the day to keep the soil moist all of the time. This frequent watering is necessary because the small root system doesn’t extend into the soil.
In general, water your seed or sod for five to ten minutes two to three times a day. It’s best to water once in the morning and then again in the afternoon, avoiding the hottest part of the day.
How much water does your lawn need?
The exact amount you water depends on the type of grass you’re growing and the time of year.
- Cool-season grasses grown in northern climates typically need about 1” of water weekly. Kentucky bluegrass, perennial ryegrass, and tall and fine fescue are all cool-season types. Ideally, you want to split this weekly requirement into two or three watering events evenly throughout the week.
- Warm-season grasses grown in southern climates usually need a little less water than their cool-season counterparts. Unlike St. Augustine grass, which needs 1.25” of water a week, most warm-season turfs need three-quarters to an inch weekly. Zoysia, centipedegrass, Bahia, and Bermuda tend to grow deeper root systems, so you can water them once or twice a week.