How Long Does it Take for Grass Seed to Grow Fully and Other Seed-Growing Tips

By Brian Mounts | Jun 13, 2020
How Long Does it Take for Grass Seed to Grow

You might be thinking about starting a new lawn by seeding or over-seeding your existing lawn with fresh baby grass. Either way, knowing how long it will take for grass seeds to sprout and then establish can help you plan an effective timeline for your lawn care regimen and get a better lawn faster with as few mistakes as possible. Let’s get into the details.

On average grass seed takes approximately 7-14 days to germinate depending on the seed variety and then another 2-3 weeks to mature enough to start mowing just like your existing or old lawn. Each variety has its own expected timeline that differs slightly from these averages.

For instance Ryegrass will germinate and establish faster than the average seed while Kentucky Bluegrass will be slower. Some grass types like St. Augustine will be nearly impossible for average homeowners to get to sprout and establish; for this reason this grass type is rarely grown from seed and most frequently installed by sod or plugs.

Below I’ve included a table or chart of grass seed growth patterns to expect for your next lawn seeding project.

Chart of Grass Seed Grow Time: Expectations For Optimal Grow Conditions

The exact time that it takes for a grass seed to germinate – that is, transition from a seed into a grass plant – varies greatly by the type of grass seed. Not every type grows at the same rate or thickness. In addition, certain seed varieties respond better to certain application techniques, climate conditions, and/or watering strategies than other varieties.

Let’s go over some common grass seed types that you might be considering for your yard. In all cases below the growth time estimates will be based on optimal conditions.

Varieties of Grass Seed

Grass Type Time To
Germinate
Time To
Establish
Total Time
Seed-to-First Mow
Perennial Rye 5-10 Days 15-25 Days 20-35 Days
Kentucky Bluegrass 12-17 Days 14-21 Days 26-38 Days
Fine Fescue 10-14 Days 20-31 Days 30-45 Days
Tall Fescue 10-14 Days 20-31 Days 30-45 Days
Bentgrass 7-15 Days 15-25 Days 22-40 Days
Bermuda Grass 7-14 Days 21-35 Days 28-49 Days
Centipede 10-25 Days 15-25 Days 25-50 Days
Zoysia 14-21 Days 15-25 Days 29-45 Days
Carpetgrass 14-21 Days 25-40 Days 39-61 Days

Note: St. Augustine is another grass type that is not usually grown from seed but rather installed as plugs or sod from professional grass suppliers.

  • Buffalo grass will take about 14-30 days to grow fully.
  • Rough bluegrass will usually only start to grow between days 7 and 10.

If you put seed down in the early Fall then these times will be mostly accurate so long as you prepare the soil correctly for new grass and also keep keep the seeds adequately moist while they germinate.

Factors That Can Slow Down Grass Germination

If your local temps are lower or higher than normal or you are having trouble with keeping the seeds watered regularly then these timelines will likely extend out further unless you get really lucky.

If you don’t keep your seeds moist it will take longer for the seeds to germinate and you may hinder full germination leaving you with spotty coverage. Also, if the soil is overly compacted this will also make it harder for young root growth to push down deep into the ground. Shallow roots will cause grass to grow slower and may make it hard for the new blades to stay alive.

This post should give you more ideas to encourage deeper root growth in grass.

Considering these timelines are based on optimal growing conditions you’ll probably want to spend a few days up front preparing the ground for the planting of new grass seed by loosening your topsoil, aerating, dethatching, and deep watering. If you check for nutrient, oxygen, and pH levels these can be corrected ahead of time too with a few extra steps.

Obviously this can all take a few extra days before the planting itself, so include these in your schedule or calendar when considering planting a new lawn that’s full of grass.

Germination for grass seeds requires many different things to go right for it to occur. Grass seeds need to be appropriately watered and nourished and their environment needs to be undisturbed enough so that the new, young shoots can poke through the ground and start to soak up sunlight.

Next we’re going to go into greater depth on all of the main factors that will impact your seed germination rate, timing, and overall success.

Effects of Seed Density in Your Yard – Over & Under Seeding

It’s always a bad idea to put too many seeds onto your yard when you’re just starting out. If you put too much seed down then all you’ll be doing is forcing your little seedlings to compete with each other for valuable nutrients, water, and oxygen.

It makes sense to put down more seed than a package mihgt recommend but as most grass types mature their crowns will put up multiple blades and will eventually look and feel thicker than seedlings. When grass sprouts are still young a lawn may look thin but after another couple of months each plant will be more dense and the entire lawn will look and feel full. Keeping the spacing less dense will be a driver to the overall health of the lawn.

In order to avoid sowing too much grass seed in your yard, you’ll want to follow the recommendations on the back of a given seed’s packaging and follow the guidelines we’ve published in this guide. Putting the seed down in the right weather conditions and in prepared soil with a perfect watering schedule will make a heathly thick lawn with less seed.

Conversely, you don’t want to seed too few new grass plants otherwise your new lawn will be patchy in some areas and won’t feel as full like it should feel. A thin lawn looks aesthetically unattractive and can lead to competition from weeds throughout the turf especially ion the thinnest patchy spots. The only exception might be when you are sowing a grass type that spreads laterally via rhizomes and/or stolons but even then thin grass invites weed infestations so it’s not recommended.

If You Have An Existing Lawn That’s Thin

The only time that you should overseed your yard is when your existing yard is thin and its appearance is patchy or when you want to blend two grass types for a specific purpose like adding color to a lawn when it might otherwise go dormant.

Overseeding will speed up the process of making a lawn thicker and fuller in less time, especially when you overseed in the fall.

If you do opt to overseed you’ll spread new grass seeds throughout your lawn in the early fall right after dethatching and aerating. This helps the seed get contact with the soil and then allows the grass roots to more easily penetrate the soil and reach deep down before the winter freeze.

You can read more about when to aerating your lawn here and how often you can or should dethatch your lawn here.

When you overseed you’ll need to make sure that you water these areas just like you would if you were seeding a new lawn for the right amount of time. This may require a special sprinkler timer to go off for a few weeks during the germination period while being careful to not let the area get overwatered by your existing sprinkler setup.

You can see this post for more on how when to stop watering in the fall.

If you overwater only some of the grass seeds will sprout, but that’s usually alright in an overseeding scenario; you only want some of them to grow to maturity to plug the gaps in your lawn. Seed that falls in dense patches isn’t necessary and any new sprouts will help an existing lawn more than doing nothing.

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

How to Spread Seed Correctly

First off, you’ll want to check the instructions on the back of your seed’s packaging to see the recommended seeding rates. This can vary drastically depending on your seed species.

You can also see this post for guidelines on how much seed you need to put down for various grass types.

Once you’ve learned the optimal amount for your grass type it’s a good idea to rely on a seed spread spreader instead of just using your hand. Spreaders will drop the seed evenly across your lawn automatically as a result of their construction. Some spreaders are perfect for moving in tight spaces or wide open lawns depending on your needs.

This post fully compares drop spreaders and broadcast spreaders and may be worth a read.

Before You Seed The Lawn
you’ll want to loosen the soil up to allow tender roots to be able to penetrate the surface and establish. Depending on your level of soil compaction this could be just a light raking or a small tilling job. One the soil is loose I like to deeply water the soil so that it’s moist way down into the root zone that way it doesn’t dry out during the germination phase where deep watering is not possible.

After You’ve Seeded The Lawn
You’ll want to use a rake and lightly work the seeds into the soil. Don’t dig them deep; aim for about one-fourth of an inch for most species unless otherwise specified on the back of your seed packaging. The goal here is to ensure seed-to-soil contact as this makes germination possible.

You can make sure this happens by going over the soil with a roller to press the seeds down into the soil and make sure that they’ve been compacted properly and are secure against wind and water movement or disturbances.

Will Grass Seed Grow If It’s Just Sitting On Top of the Dirt?

I also like to lightly spread a bit of peat moss, or even better, coconut coir on top to help retain moisture.

The Soil Temperature Greatly Affects Germination Rates

Soil temperature is another important factor that might impact seed growth speed and health.

First off, it’s important that you only get a grass type that is workable for your climate and typical soil temperature for the season. This means avoiding warm soil grass if, for instance, you have cool grass during the current season. For instance, northern areas of America will handle cool season grass better than warm season grass, while southern states will experience the opposite effect.

Cool Season Grasses

  • Ryegrass, Fescue, Bluegrass, and Bentgrass
  • Ideal Temperature: 60-75 degrees

Warm Seasons Grasses

  • Centipede, Zoysia, Buffalo, Bermuda, and Bahiagrass
  • Ideal Temperature: 80-95 degrees

Grasses need to have soil within these temperature ranges in order to grow healthily and along their standard timeline. If you have soil at an edge case, you may still manage to grow healthy grass, but it might take longer than it would otherwise, particularly if your seed is typically a warm grass type.

Quick Fun ReadEver Wonder Why Grass Makes You Itch?

Watering Effects on the Growth Time of Grass

It seems obvious, but it has to be said: watering is incredibly important when it comes to keeping your grass growing quickly and consistently. However, too many beginning gardeners will overwater their grass and end up drowning it in moisture. This is just as bad as not watering your new grass seedless at all.

Related Reading: Can You Water Grass Seed Too Much?

The key to proper watering is getting the soil to be moist but not soaked. The best way to achieve this optimal level of moistening is to water by hand, instead of by sprinkler. While you can achieve good watering practice with a sprinkler, you’ll need to watch the process carefully and adjust your sprinkler system to be as close to the goal as possible.

Instead, watering your new lawn by hand gives you total control over your watering intensity. You can do this with a garden or house hose and a good nozzle, particularly the kinds that fan water out over a large area in a short amount of time.

You should aim to make the soil moist and a good environment for your seeds twice a day, once in the morning and once in the evening. Failing to do this may cause your seeds’ growth to stagnate, which will add time to their overall development. In the worst-case scenario, your seeds may die out, requiring you to purchase new seeds and start again.

Finally, one final watering tip is to moisten the soil a day before you actually plant. This will ensure that the soil is perfect and ready to receive the seeds when you plant the next day.

Once your grass has grown, sprinkler systems are a fantastic way to make sure that your lawn gets the daily hydration it needs to be healthy. We’d recommend finding a sprinkler system that can reach your entire lawn easily in a wide arc.

Nourishment or Soil Health

It’s important that your soil is nourishing enough for your grass seeds to grow with all of their capability. Soil that doesn’t have enough nutrients as part of its composition will prove to be a poor starting point for your new grass.

You can test your soil for pH level and oxygen content: two factors that determine whether a given soil is a good environment for seedlings of all types of plants. It’s usually very easy to find the pH level required by a given seed type on the back of their package or container.

In the event that you don’t have a soil with the right pH level, you can always mix in fresh soil with an offsetting pH balance to change your soil’s composition. These products can be bought in many places where you can buy grass seeds. In addition, you should aerate your soil every year to open it up for oxygen storage for fresh and current seeds. This is usually done by a lawn aerator, which churns up the ground and opens holes for oxygen to sink into.

Birds Can Mess it All UP!

Birds can very easily drive up the amount of time it takes for you to grow a new lawn full of fresh grass. Birds love fresh seeds, as they are easy food sources and are usually devoid of any predators (except the occasional dog!).

However, there are definitely steps that you can take to stop birds from eating the majority of your grass seeds and slowing your overall progress. For starters, you can spread a layer of straw atop your newly planted grass seeds. This will confuse the birds and prevent them from recognizing the abundance of seeds right beneath their wings.

You can also try to scare the birds away frequently by yourself or through the use of the dog, although this requires more constant attention and vigilance for the duration of the growing period.

Hilly Areas Make Growing Grass Harder

One final factor that might be affecting your seed success is whether or not you’ve been spreading grass seeds over hilly areas. Oftentimes, you might need to oversee the hills or bumpy terrain since grass seeds are more easily washed away by wind and rain if they are at an incline.

Overseeding, in this case, can be beneficial since you’ll be basically ensuring that some of the grass seeds will stick around and grow into shoots while the others are washed away and are necessary casualties for the success of the lawn as a whole.

Read MoreHow to Grow Grass on a Steep Hill

Conclusion

As you can see, there are tons of factors that can affect how long it takes for your grass seed to grow fully. But so long as you control all of the factors above and choose the right seed for your climate and lawn conditions, you should have fresh, beautiful grass within a few weeks at the most. Enjoy your new lawn!