When to Stop Watering New Grass Seed?

By Brian Mounts | Jun 24, 2020
When to Stop Watering New Grass Seed

There are few more inviting sights than a stretch of healthy green lawn on a sunny day and that’s why we put grass seed down in the first place. If you are growing grass from seed to enjoy your own yard this summer then you may need to consider when the best time is to stop watering your new grass seed and switch over to a regular lawn watering schedule.

You can stop daily watering of new grass seed once it is fully established; that is, once it has germinated and the grass blades are about an inch tall. This will be after a period of about three weeks to a month from seeding. At this stage, you can start a regular routine of watering once or twice a week for a total of around an inch of water.

You can see this post for more detail on different types of grasses and how long they take to fully grow.

The secret of establishing a good lawn is to maintain sufficient—but not too much—moisture in the soil so that the grass seeds do not dry out. If they dry out, they die. At the same time, you don’t want to drown them.

Overwatering can be just as deadly through washing the seeds away or depriving them of enough oxygen.

Preparing the Ground

You can usually cultivate a good lawn in one of three ways: scattering new grass seed in prepared soil, laying down turf lawn sod (“instant lawn”), or overseeding an existing lawn with grass seed to encourage further growth. We’ll focus on the first scenario: planting new grass seed.

The early stages of growing your lawn through any of these methods are remarkably similar. The first thing you should do is soil preparation.

See my full grass growing guide here for more helpful tips – no opt-in needed.

Like most projects, the end success usually depends on the preparation stage, and you only have one chance to get it right. You won’t get to the stage of even thinking about when to stop watering new grass seed unless the ground has been adequately prepared to sustain the early growth.

In its simplest form, preparing the soil means loosening it up so that the seed has ample opportunity to make contact with the surrounding soil. Soil preparation can be done with a steel rake or dethatcher to ensure that the ground is loose, evenly spread, and free of stones.

Mixing in a little compost or fertilizer, especially phosphorus, at this stage will enrich the soil.

We’ve already mentioned the importance of moisture for growth, so once you have loosened the ground you will plant by raking or tilling, you need to thoroughly water the area to moisten the soil to a depth of six to eight inches.

You should perform this watering two or three days before you start planting the new seed.

You can test the depth of moisture in the tilled soil by inserting a long screwdriver; if it goes in easily, you probably have the right consistency.

Avoid walking on the tilled soil at this stage, and for the first two or three weeks after seeding. This will create depressions and cause soil compaction, which will affect the seeding consistency and create little puddles when watering.

When to Plant

The key is to fit in with nature’s cycle of growth. Nature relies on three conditions for growth: warmth, moisture, and sunlight. Autumn and spring usually provide these ideal growing conditions, so this means paying attention to the climate in which you live and the type of seed you wish to plant.

Cool-season grasses are best suited to temperate and cooler climates in the north, and warm-season grasses are better suited to southern climates.

Cool-season varieties are best planted early in the fall, around September in the northern hemisphere. At this time, the ground is still warm enough from summer to encourage germination.

Spring (April/May) is also an excellent time to plant, with its mild temperatures and good rainfall—but then your new grass is competing with the rest of nature’s new growth, including weeds!

Warm-season grasses fare better when planted in late spring or early summertime. Soil temperature needs to be around 45°F for consistent germination, which means that air temperature needs to be above 50°F. Keep an eye on your barometer before deciding to plant new seed.

Trying to plant any new seed in the hot summer months and so-called “dormant seeding” during winter is often a waste of time and money. The ideal conditions described above are just not there, and you’re fighting against everything that nature has taught us.

Germination and Mulching

So you’ve spread your new seed and raked it over lightly so that it is covered with a thin layer of soil. What now? Sit back and wait for it to sprout? Well, no. You can take some consolation in the fact that you’ve done most of the hard work, but this stage of seed germination is critical to the success of your new lawn.

Germination is the process of growth that happens when the seed absorbs enough moisture to start sprouting. Depending on the type of grass and the soil temperature and moisture content, this may take anything from three to thirty days—usually about two to three weeks.

To encourage this process, you will have covered the newly planted seed with a thin layer of mulch—compost, straw, or manure, which helps to retain moisture in the soil and provides protection from the sun and marauding birds looking for a free meal.

Germination is another stage where you will avoid walking across your seedbed or dragging hosees and sprinklers across the area. This will disturb the seeds and unevenly redistribute your carefully laid mulch.

What type of mulch you choose will depend to some extent on your budget. Store-bought compost and a variety of commercial mulch/fertilizer combinations are excellent but pricey because they contain nutrients that leech into the soil.

Still, there are a variety of straws that are inexpensive and effective; the grass grows up through the straw, and it eventually breaks down with the first couple of mows.

Watering in the First Month

The time it takes for the first blades of grass to appear — anything from a week to a month — requires patience, with a focus on keeping the seeds moist but not swimming. How much water you give them will depend on several variables: the ambient temperature, the local rainfall, sunshine and shade, and so on.

As a general rule of thumb, to maintain the level of moisture needed for germination, you should be watering twice a day for about 10 to 15 minutes. The best times for watering are in the early morning — before 10 a.m. — when there is a lower chance of evaporation due to sunlight and wind.

This also allows the lawn the rest of the day to dry, which discourages disease and root blight.

A second watering is required in the late afternoon, again allowing time for the lawn to dry out before nightfall. You don’t want your new grass seed to stand in water overnight; this will suffocate it and also make the grass more prone to disease.

The objective of this watering routine is to moisten the soil to seed depth, that is, to a depth of about two inches (source).

When to Stop Daily Watering

Not all seeds will germinate at the same time, so you must continue this twice-daily watering routine until all seeds have germinated. How will you know when this is the case? You will know when you can see an even and consistent growth of green sprouts across the area of seeding.

Grasses are known as “monocots,” meaning that they sprout from the soil as a single blade. This means that your new lawn might look pretty sparse at first. In time, however, the plant will grow and spread into a larger plant.

This will take time—up to a year or maybe even two — depending on the climate, especially if you have started from scratch with a bare patch of soil and new grass seed.

Once the grass shoots are a couple of inches tall, substitute the twice-daily light watering routine for light watering every second or third day, depending on the weather. You can consider your first mowing when the grass is three to four inches tall.

By this stage, root growth is established and a deeper watering, soaking the soil up to four inches underground, can be carried out less frequently. Allowing the soil to dry out before watering again encourages the roots to grow deeper in search of nutrients and moisture.

First Mowing

Until your lawn is well-established — in other words, in the case of a new lawn, until a couple of seasons have passed — do not mow your grass too short. Keep your mower at its proper highest setting, no less than three inches.
This will continue to provide your yard with protection against moisture loss, especially in warmer climates and heat spells.

With an established lawn, you’ll want to water once a week to provide at least an inch of water, either in one deep watering or two shorter spells.

Final Thoughts

The key to nurturing a great new lawn is to maintain the right level of moisture at various stages of the process. Knowing when to taper off that moisture level is as important for the long-term health and maintenance of your lawn, allowing it to become the centerpiece of your garden.

Now with that out of the way take some time to learn a bit more on any of the following related guides:

Can You Grow Seed Sitting On Top of the Soil?
How to Stop Birds From Eating Your Grass Seed
How Long Should You Water Grass Seeds

Lastly, Make Sure To Not Overwater Your Baby Grass

Until the grass shoots start coming out of the soil you need to keep the soil wet all the time without producing pools of water which can unevenly spread the seed and hinder germination. After this point however it’s safe to assume that the plant has rooted strongly started to grow.

While you still have to continue watering it regularly and deeply you still do not want to overdo it. It is super easy to overwater the plant at this point, and a lot of people end up doing it.

Make sure to see this full article on the problems that come with overwatering grass seed and your lawn.

Here are some more related posts that you may find interesting:

Why Does Grass Make You Itchy
Is It OK to Water The Lawn at Night?
How to Grow Grass on a Steep Hill?
How to pull up grass?