Got bald spots?
In your lawn, that is!
You’re probably wondering, does grass spread on its own?
And it’s a good question. After all, why bother re-seeding a bare patch if there’s a chance your lawn will take care of itself?
I’m going to explain the different ways that different grass species spread so you can work out your plan of action.
- How Does Grass Spread?
- Things That Stop Grass Spreading
- Things You Can Do to Help Grass Spread
Disclosure: This post may contain affiliate links. If you shop through the links on YardThyme, we may earn an affiliate's commission from qualifying purchases at no additional cost to you. For more information, read full disclosure here.
How Does Grass Spread?
Different species of grass spread in different ways, and some don’t spread particularly effectively at all.
The four ways that grasses spread are through underground rhizomes, above ground stolons, bunching, and going to seed.
Since most lawn owners mow their lawn often enough that the grass isn’t left to go to seed, the only real mechanisms for spread are through rhizomes, stolons or bunching.
Spreading via rhizomes and stolons can be effective. Spreading via bunching is a slow process.
Rhizomes are underground root systems that spread laterally, or sideways, throwing up clones of the mother plant as they grow.
Above ground, it can look like new grass has sprouted, but really, everything is connected underground.
Common lawn grasses that spread via rhizomes include Bahia grass, Bermuda grass, Kentucky bluegrass, St Augustine and Zoysia grass.
Stolons are stems that grow horizontally above ground. Each time a node forms, a new shoot will grow upwards. As with rhizomes, at a glance it can look like a new plant, but really, each of these shoots is a clone of the mother plant.
Spreading via stolons can be an effective way for lawn grass to cover bare patches.
Common lawn grasses that spread via stolons include Bahia grass, Bent grass, Bermuda grass, Buffalo grass, Centipede grass, St. Augustine and Zoysia grass.
Bunching is the least effective method of spreading for grass species. It occurs when grasses that naturally grow in a bunched formation, slowly increase the number of stems in each bunch over time.
Each new stem that grows out of the side of the bunch is called a tiller. As the number of tillers increases, the size of the bunch gets bigger.
Tall Fescue and Ryegrass are bunching grasses and don’t spread effectively to cover bare patches.
If you have Tall Fescue or Ryegrass in your garden, you will need to manually overseed your lawn to keep it dense and cover bare patches.
Alternatively, you can overseed with a different grass species that spreads via stolons and rhizomes. Have a read of this article to work out which species is best for your region.
Going to Seed
When grasses are left to grow long enough and go through all of the phases of their reproductive cycle, they will release seeds which can travel varying distances and sprout new plants.
Unlike spreading via rhizomes or stolons, the plants that grow from new seeds are completely new plants, independent of their parents. However, few lawns are left to grow long enough for seeds to be released.
Some lawn species have adapted to release seeds at shorter heights in response to mowing practices. However, it’s also possible that your grass is a hybrid species whose seed will be sterile anyway.
All in all, relying on your lawn grass to spread seed itself is risky and will probably end in disappointment.
Things That Stop Grass Spreading
If we ignore seed, the three remaining ways of grass spreading depend quite heavily on the lawn being healthy. An unhealthy lawn won’t have the energy or resources to put into spreading and will be unlikely to cover bald patches without more help.
But there are also environmental factors that can inhibit spreading too.
If there is a part of your lawn that is in shade for the majority of the day, grass will not grow there. All grass requires direct sunlight for a significant portion of the day to grow well.
If you have a shady patch of lawn and you are struggling to encourage grass growth there, your best bet would be to replace that area of your lawn with something like paving stones, wood chip and shade tolerant plants, or moss. Have a read of this article for more lawn-free yard ideas.
Alternatively, St Augustine grass and clover tolerate partial shade.
Too much or too little water will affect how easily your grass spreads. If a part of your lawn gets flooded frequently, or you are experiencing a drought, the grass will conserve its energy and not spread until conditions are right.
Most grass species don’t tolerate salt very well. So, if your soil is high in salt, the grass will find it harder to spread and cover bald patches.
The type of soil you have is particularly important if you have a lawn grass species that spreads via rhizomes. Since rhizomes grow underground, soil that is heavy and clay-based will hinder their progress.
Conversely, if you have a soil type that is nice and loose, with good drainage, the rhizomes will travel easily.
Lawn Thatch or Compaction
If your lawn has excessive amounts of thatch, or the soil is compacted, these are also things that will prevent effective spreading via stolons and rhizomes respectively.
Luckily, both of these problems can be remedied by dethatching and aerating.
Wrong Time of Year
All of the above have been accounted for and your grass still isn’t spreading? It may not be in its active growing phase.
Grass doesn’t grow all year round. Most lawn species are cool-season grasses which only grow noticeably in spring and fall. Warm season grasses mostly grow in the summer. All grass species have times of year when they are only growing very slowly, if at all.
If your grass isn’t in its active growing phase, be patient, it will come into its own soon!
Things You Can Do to Help Grass Spread
Practice Good Lawn Care
Keeping your lawn healthy and lush is the best way to prevent weedy invasions, while also ensuring that bare patches are either prevented, or covered quickly.
It can be a bit overwhelming so I have created a lawn care calendar that I find super helpful. You might too!
Fertilizer isn’t essential for all lawns. However, if you have poor soil quality, improving your soil with a good organic fertilizer will definitely help your lawn spread.
However, it’s important not to fertilize too often or when your grass isn’t in an active growing phase as this will do more harm than good.
Read more about how often to fertilize your garden here.
Another great thing you can do for your lawn is to leave your grass clippings on the lawn. Provided there isn’t a thick layer that will block sunlight from reaching the grass, leaving the clippings to break down actually provides a natural fertilizer – and it’s free!
I’ve got a whole article dedicated to what to do with lawn clippings that is a must-read. Under no circumstances should grass clippings be sent to the landfill.
Making sure your grass gets the right amount of water is important for healthy roots.
Doing frequent, light waterings is actually counterproductive to root growth.
Grass actually performs best with a deeper watering, twice per week. Read more about how to water correctly here.
Just like watering and fertilizing, did you know that there are right and wrong ways to mow?
Many people actually mow too short!
Making sure that you adjust your mower height depending on the season can be the difference between a healthy and unhealthy lawn.
Since photosynthesis is inherent to grass survival, removing too much of the grass blade each time you mow makes it very hard for your grass to get the nutrients it needs to stay healthy.
If your grass isn’t getting enough nutrients, it is unlikely to spread.
Have a read of this article to learn all about mowing heights, and if in doubt, leave your grass longer.
If you need a quicker fix and don’t want to wait for the grass that you already have to cover the bald spots in your lawn, overseeding is a good option.
You can either focus on just the bald spots, or give your entire lawn a boost.
Overseeding a lawn is an effective way to ensure that weeds don’t get a chance to establish themselves. It’s surprisingly easy to do. I’ve got a guide on how to overseed a lawn that explains everything you need to know. It’s also effective if you already have weeds in your lawn – give it a try!
Does grass spread to fill in bare spots?
Some species of grass spread to cover bare spots and some don’t. Whether your grass will spread effectively depends on what species it is and what conditions it is growing in.
How to make grass spread faster?
Grass that is healthy, gets adequate sunlight and water, and is in its active growing phase, will spread easily without any help (assuming it is a grass that forms rhizomes and stolons).
Keep your lawn healthy by practicing good lawn care, as described above.
Alternatively, if you have a grass type that forms bunches, nothing you do will help it to spread. You’ll need to overseed.
How long does grass need to spread?
Grass species that spread by rhizomes and stolons should do so in a few months if conditions are right. This means the right time of year, right amount of water, sun, nutrients, and soil conditions. However, waiting for the grass to spread by itself is usually slower than applying a new seed.
What kind of grass spreads the fastest?
Grasses that spread via rhizomes and stolons grow the fastest. Bermuda grass in particular is a fast spreader.
How deep do grass rhizomes go?
Grass rhizomes can be as deep as two feet when conditions are right.
That brings us to the end of this article on how grass spreads.
Hopefully, you understand the different ways that grass can spread and what you can do to help it.
At the end of the day, it all comes down to lawn care and getting it right. However, if you have visible bald patches on your lawn, your best bet in most cases is to overseed those patches rather than waiting for the grass to spread on its own.
Did you find this article helpful? If you did, please let your friends know where to come for yard care advice, and feel free to comment if you have anything to add.