What is the Best Time to Water Grass Seed?

Watering grass seed- how hard can it be? Watering new grass seed may seem as simple as dumping water on your lawn every so often, but there’s a lot more to it. 

Adding too little water can dry out the seeds and eventually kill the little sprouts, and overwatering can wash away the seeds that have not even taken root. 

Apart from watering grass seed, there are other factors that determine the healthy growth of seeds including the time of year you spread new grass seed, the frequency of watering, the time you water, and whether or not you mulch. 

The best time to water grass seed is in the morning, and there are several good reasons for this time. What you should NEVER do is water grass seed at night regardless of the species of turfgrass. 

Key Takeaways On Watering New Grass Seeds 

1. Prepare the Soil 

It’s important to create a welcoming area for your new grass seed by preparing the soil. If you have a layer of thatch between 1/2 to 3/4 inches, consider using a dethatcher or a power rake to remove the debris so that the new seeds have better contact with the soil. 

If you’re planting a new lawn on bare soil, use a steel rake to loosen the top half-inch of soil to easily rake the seeds in after spreading. 

Man raking soil

You can now perform a soil test to check whether the soil could benefit from starter fertilizer. I usually wait for two weeks after seeding before applying fertilizer, because the fertilizer starts working at the same time when the seeds begin germinating. 

2. Spread and Cover the Seeds 

Next, use a rotary or drop spreader to spread the seeds on the soil, and then rake lightly to cover the seeds with soil. 

3. Water the Seeds Daily 

Water the seeds at least twice a day to prevent the soil from completely drying out. Do not overwater or soak the lawn because you risk washing some of the seeds away.

4. Watering After Seeds have Sprouted 

Continue watering lightly after the seeds have sprouted, and wait for the soil to dry before watering again. It is even more important at the seedling stage to not saturate the soil repeatedly, as it may kill the new grassroots, and lead to serious diseases such as Pythium blight. 

When your grass reaches a couple of inches tall, cut back on watering to just once every two to three days, depending on the temperature. 

Young Grass Sprouts

Why is Morning the Best Time to Water Grass Seed? 

The absolute best time to water grass seed is between 6 am and 10 am and here’s why! Calm breezes and cooler temperatures during this time slot greatly reduce the chances of evaporation and keep the soil and seeds cooler for the hottest parts of the day. 

And when the seeds are cool during the hottest moments of the day, there are considerably fewer chances of the occurrence of heat stress. 

But that isn’t the only reason, watering grass seed when the are heavy winds or breezes like midday moves the condensation from the water and your sprinklers away from your grass seed, but condensation will end up directly on your grass seed when you water before 10 am. 

This ensures that you don’t lose any water, and in fact, will use less water to keep your grass seeds hydrated, and eliminate the chances of bare spots and patches. 

Why You Shouldn’t Water Grass Seed at Night? 

Many homeowners believe that watering grass seed at night offers several advantages such as reduced evaporation, cooler temperatures, and reduced water use.

But there’s a small issue with watering at night; if you think evaporation during the daytime is bad, then zero evaporation could be much worse. 

You should avoid watering grass seed at night, as the water will sit there for too long, increasing the risk of fungal disease during the germination process. This excess water in your lawn will stay there for a while because there’s no sun to evaporate the water. 

Watering Grass

When to Water Cool-Season Grasses vs. Warm Season Grasses? 

Both types of grasses should be watered between 6 am and 10 am in the morning. However, cool-season grasses like tall fescue need more water than warm-season grasses during the active season, which is spring and fall for cool-season grasses and mid-to-late spring through early fall for warm-season grasses. 

Take for example Kentucky Bluegrass, a cool-season grass that requires 1½ to 2 inches per week of watering on average in the active season compared to Bermudagrass, a warm-season grass that requires just 1 to 1¼ inches of water weekly in the active season. The depth of the water will depend on several factors such as your general climate, soil type, and most importantly how often you water. 

How Long and Often to Water New Grass Seed? 

Ready to spread grass seeds and sprinkle water over them and watch them grow? Wait, not so fast! Before even spreading new grass seeds, you have to prepare the soil first by sprinkling 6″ to 8″ water deep into the soil

This is a crucial irrigation step, and skipping it may cause the grass seeds to not root well in the soil, and in worse cases dry up and die shortly after being planted. 

After you spread the seeds over the moist soil, it’s a good idea to cover them with a thin layer of mulch before watering the new grass seeds even once. 

Spreading mulch over new grass seeds before watering helps retain moisture and prevents the seeds from drying out. When it comes to mulch, there are several options to choose from including wheat, barley, oat straw, compost, or aged pine straw. 

dark soil and grass seed with mulch and green lawn

Water new grass seed 5 – 10 minutes immediately after planting to ensure the first several inches of the soil are moist. But don’t get carried away and over-water grass seed because some types of soil can get spongy, so water for 5 – 10 minutes per session, twice a day. 

How much to water new grass seed
Image Credit – https://gilmour.com/

Following this schedule will ensure that you replace any water that has evaporated without oversaturation. Once the grass seeds germinate, which takes between 5 – 10 days depending on the species, you can stop watering twice a day but switch to a longer once-a-day watering schedule anytime between 6 am and 10 am. 

As time goes by, the frequency of watering should be reduced to around 40 minutes on alternate days, and then gradually to 2 – 3 times per week. The primary goal of watering after the seeds germinate is to help the grass form deeper roots, for which less watering is required. 

Also, be sure to check real-time weather data for any showers in the forecast to decide whether you need to water grass seed that particular day. 

Pro Tip: Spread grass seeds on bare soil, and not over grass, leaves, or other lawn debris. 

Watering New Grass Seed - Learn How Long, How Often, How Much and Best Times to Water New Grass

How to Know if Your Grass Seeds are Getting the Right Amount of Water? 

There are multiple easy ways of determining when your grass seeds are thirsty including rain gauges, sensors, and the good ol’ can test. 

1. Can Test 

Place around 8 empty tuna or cat food cans randomly throughout your lawn, some near the sprinkler head, and others several feet away. 

Turn on your irrigation system or manual sprinkler for approximately 15 minutes, and use a ruler to measure the depth of water in each can. 

Refer to the lawn watering depth chart below to determine the number of minutes you should water each week. Take note that these watering schedules can be affected by the weather, so increase watering during humid and dry weather. 

lawn watering depth chart
Image Credit – https://static.spokanecity.org/ 

2. Use a Long Screw 

Another easy way of checking the depth of water penetration is by using a long screw. Insert the screw into the ground about 6 – 8 inches, and if you don’t feel any resistance, you have the right water saturation.

3. Install a Rain Sensor 

Rain can affect your normal irrigation schedule, given that there’s no way for your automatic sprinkler system to detect rainfall in-between watering sessions.

Installing a rain sensor stops your sprinkler system from automatically watering when it detects dry conditions. A rain sensor only works effectively when installed in the right location, which is ideally any area in your yard that’s free from obstructions. 
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What Factors Impact Watering Schedules? 

There are some factors beyond your control that can affect your ground irrigation schedule. For example, you should water more frequently when it’s dry outside, and you don’t need to water as much during rainy weather. 

But have you considered windy weather, because your seeds will blow away if it’s both dry and windy outside? If you know of any windy and dry days, you don’t have to add lots of water, but just mist the soil a bit, so that the seeds can sink slightly into the soil, and receive an extra bit of protection. 

Furthermore, it’s worth noting that not all grass seed brands and varieties are built the same, meaning that the varieties that germinate quickly will need light watering than slower-growing grass seed varieties. 

Can I Spread Grass Seed in the Winter? Do I need to Water My Lawn in the Winter? 

This may sound like a silly question, but “dormant seeding” is actually a thing! Just because the snow has come and gone, temperatures have risen just a bit to thaw your winter wonderland, and your lawn is muddy, murky, and patchy, you can still seed your lawn now, and get a head start on spring growth. 

While there’s little value in scattering grass seeds over the winter, doing so does allow the seeds to blend in with the soil before germinating. 

You don’t really need to water your lawn in the winter because the snow and rain provide the right amount of moisture for both warm-season and cool-season grasses during this time. 

Hand Watering vs. Sprinkler Irrigation System 

Grass seeds, turfgrass, and annual beds need a good drink, again, and again, and again. Even though Mother Nature lends a helping hand at times with a nice rain shower, you are ideally in charge of providing new grass seed with the right amount of water consistently, which to reiterate is 10 minutes of watering morning and evening until the grass seeds have germinated. 

To water lawns and new grass seed, you have two options to choose from:

  • Hand-Watering
  • Sprinkler Systems

So, which option is right for you? Well, the answer depends on several factors, but remember we’re talking about watering new grass seed, which requires frequent watering until the seeds settle in. 

Hand Watering

Hand Watering Grass

Hand watering may seem easy, where you grab a hose and pour water on new grass seeds, right? But, lots of grass seeds owe their slow, dry death owing to this philosophy. 

Most people know how to hand water a lawn, but very few know how to water new grass seed and existing lawns effectively. With regards to new grass seeds, you can’t just splash some water on them or call it good after a little drizzle. 

Like I said before, you need to water, again and again, which many people just don’t have the time for! Hand-watering requires your full attention, and knowledge about how much water to provide for new grass seeds in all stages of growth. 

While hand watering is a great way to stay in tune with your lawn, there’s a lot of trial and error with this method. 

Sprinkler System

One of the greatest benefits of installing a sprinkler system to grow a lawn from scratch is that it is incredibly convenient. 

Irrigation options can be as simple as hose-end sprinklers, oscillating sprinklers, handheld sprinklers to self-cleaning smart irrigation systems. 

Smart irrigation systems are a great choice for new seed plantations, small square footage areas, and sprawling lawns. Put simply, smart irrigation systems ensure nothing is missed and can water new grass seed in a matter of minutes. 

On the downside, a smart sprinkler setup can be pricey, but it’s worth doing the math to figure out the associated costs of installation and maintenance compared to the amount of water you’d use to hand-water new grass seed or your existing turf. 

Watering New Grass Seed – Hard Water vs. Soft Water 

Now that you’re aware of how to water new grass seeds for best results, there’s one area that’s often not touched on, that is whether you should water your lawn with hard water or soft water. 

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You probably already know the difference between hard and soft water, but to explain briefly, soft water contains fewer minerals than hard water, and only typically appears as a result of water treatments with a water softener.

Due to its rich mineral content, hard water isn’t safe for use in homes and can cause a variety of issues like stained sinks and bathtubs, scale buildup on plumbing fixtures and appliances, dry skin and hair, and a rise in water bills. 

There are both benefits and disadvantages of watering new grass seeds with hard water and soft water:

  • Extremely hard water contains certain excess minerals such as calcium and magnesium, which limit the availability of other nutrients like iron or nitrogen. 
  • Watering your lawn with soft water increases the chances of salt buildup in the topsoil, which makes it harder for new grass seeds to grow. 

If you suffer from hard water issues, consider installing a water softener in your home. And use an effective fertilizer and aerate the soil if the water gets too soft. 

When to Fertilize and Mow New Grass for Best Results? 

Wait at least four to six weeks after the seeds germinate to fertilize the soil.

Choose a fertilizer that’s high in nitrogen because this is the most important nutrient for a healthy, attractive stand of grass. 

Freshly seeded lawns need time for their roots to become established before they can be mowed for the first time, which is roughly two months. 

Final Thoughts

The best time to water new grass seeds regardless of the variety is between 6 am to 10 am. Water the grass seeds twice a day, once in the morning and again in the evening, and add some good starter fertilizer to the soil after the seeds gave germinated.