How Long Does Hydroseeding Take? (And How Long to Water It for a World-Class Finish!)

Hydroseeding can be a great way to spread grass seed, especially on sloped lawns. The process involves spraying a mixture of grass seed, mulch, water, and sometimes fertilizer over the soil. Hydroseeding is usually a more cost-effective approach than laying sod. 

In addition to saving money, hydroseeding can also save time because this process is usually more convenient than laying sod or trying to overseed a slope with a manual seed spreader. Grass seed will typically sprout within two to four weeks if it is watered three times per day for at least 10 minutes and this is done consistently for three weeks.

When Is the Best Time to Hydroseed?

The purpose of hydroseeding is to grow healthy grass and the best time to plant is when temperatures are mild with no threat of frost. Try to hydroseed in the spring at the beginning of the growing season for optimal results. 

Always plant grass after the last frost has passed. This way, the new seed will have the entire summer to become established. If it is impossible to hydroseed in the spring, wait until the cooler autumn season begins. If you choose to hydroseed in the fall, ensure that it is about six weeks before the first expected frost date.

Hydroseeding during the typical growing season but not when temperatures are too high, is key to success. A general rule of thumb is to hydroseed when the high temperatures steadily remain between 60 and 75°F (15 to 24°C). Since sprouting takes around one week and the grass will also need a few weeks to get established before the first frost, spring or early fall is usually the ideal time. 

Most importantly, do not attempt hydroseeding in the heat of summer. Extreme temperatures often cause conditions harmful to new grass seeds. Hydroseeding in the summer can doom your seeds before they even get the chance to sprout. 

Hydroseeding Advantages and Disadvantages

pros and cons
Here are some pros and cons to think about when you are considering whether to hydroseed your lawn.


  • Cost Effective

Hydroseeding is generally a much cheaper alternative to laying sod. Typically, hydroseeding costs less than 50 cents per square foot of soil. Sod usually costs over $1.00 per square foot. 

However, it is typically only cost-effective if you hire someone. Unless you already have the spraying gear, renting or buying the necessary sprayer can become expensive. Do not try to hydroseed as a cheap DIY project. 

  • Convenient

Hydroseeding sprayers allow hundreds of square feet of soil to be seeded in seconds. It is much easier to hire a professional to hydroseed the yard than to attempt laying sod or overseeding with a seed spreader.

  • Fertilizing

Hydroseeding usually includes a well-balanced mixture of seed, water, mulch, and fertilizer. Mixing fertilizer with the seed gives it a boost toward healthy germination and sprouting. 


  • Short Time-Frame

Successful hydroseeding cannot typically occur in the heat of summer. It is best to hydroseed when high temperatures are between 65 and 70°F (15 to 24°C), which is a narrow window of time for most growing zones. 

  • Not eco-friendly

Hydroseeding incorporates a bright green dye into the seed mixture so the technician can quickly identify which spots have not been seeded. This dye can contain chemicals that are less than beneficial for the environment.

How Long Should You Water Hydroseed?

While hydroseeding itself might not take very long if you have the right equipment, caring for the new seeds must be a major commitment if you want to have a good, healthy grass cover.

If you are wondering how long you should water hydroseed, follow the Rule of 3’s. Once the mulch has dried after the initial hydroseeding, the soil must be saturated three times a day for at least three weeks. In addition to the Rule of 3’s, remember that each watering session should last at least 10 minutes. 

Soaking the seed and soil daily for 30 – 60 minutes will help the seed germinate. While the soil must stay moist to grow healthy grass, there should not be puddles of water on it. For instance, if you have had several hours of heavy rain, you do not need to turn on the sprinklers immediately.

In addition to weather, the season may affect how often you should water after hydroseeding. For instance, if you are experiencing an uncharacteristically warm spring with temperatures consistently reaching 80°F (26°C) and not much rain, you will need to water more frequently or for more extended periods to keep the soil moist.

If you are having cool, rainy autumn, the soil may be retaining moisture more easily and will not require as much watering.

Can You Water Hydroseed Too Much?

water pouring bucket
While watering after hydroseeding is necessary to grow healthy grass, too much water can have the opposite effect. Water should never puddle on the newly planted soil. Too much water added after seeding can wash the seed away before it sprouts or kills the seed.

The water requirements for hydroseeding may sound excessive to beginners, but it is essential for sprouting healthy grass. Even though a vast amount of water is required, hydroseeding requires less irrigation than sod or other traditional methods of planting grass.


How Soon Can You Walk After Hydroseeding?

There should not be any foot traffic –or any other type of traffic– on a newly seeded lawn. Once hydroseeding occurs, the main priority should be keeping all people and pets off the lawn so that nothing disrupts the seed during germination.

Walking on the seed can cause it to become impacted with dirt and cut off the oxygen supply. It can also kick up seeds and prevent them from sprouting. Even when the new grass has sprouted, it does not mean it is okay to walk on it immediately.

Generally, no one should use the space until the first mowing. Once the grass reaches 2 to 3 inches (5 to 8 cm), it is healthy enough to mow. After the first mowing, the grass is mature enough to walk on. 

How Long Can Hydroseed Go Without Water?

It is essential to keep the soil constantly moist by watering it three times a day for 10 to 30  minutes for a duration of three to four weeks. Missing even one day of watering can significantly slow or stop the germination process. Plenty of water is the key to successful hydroseeding.

What Is Hydroseed’s Growth Time?

As long as the seed receives enough water, it should germinate within a couple of weeks and sprout within two to four weeks. Usually, after around six weeks, the grass is ready for its first mowing.

Mowing the lawn throughout the summer helps to ensure thicker growth and coverage of most patchy bald spots. For excessive bare patches still existing at the end of the summer, try overseeding that part of the lawn.


Hydroseeding can be an excellent way to achieve healthy, lush grass on sloped areas. It is generally easy to use and inexpensive, especially compared to heavy labor and high prices associated with laying sod. 

Find the right technician to hydroseed your yard without attempting a DIY project. The right equipment can guarantee minimal patchiness and effectively cover thousands of square feet in seconds.  

Give the hydroseed plenty of water and plenty of time to grow. In the right growing conditions, the grass seed will typically sprout within two to four weeks if it receives the correct amount of water. Within six to eight weeks, you should be able to enjoy a beautiful lawn. Continue to ensure the new grass gets plenty of water and frequent mowings to help it to spread and thicken.