What Does Potassium Do For Grass And Your Lawn?

We all want a healthy and thriving lawn filled with beautiful green grass. 

Proper care and fertilization are how we get the lawns of our dreams. 

If you’ve ever bought fertilizer for your lawn, you’ve probably noticed the NPK ratio showing the concentrations of nitrogen (N), phosphorus (P), and potassium (K). 

All of these are important for lawn health, but we’re focusing on the last part of the ratio in this article. 

So, what does potassium do for your grass and your lawn? 

Potassium is a water-soluble compound found in many lawn fertilizers. It helps with root development, winterization, stress, and resistance and strengthens the water-carrying system in plants. Potassium improves your grass and lawn’s strength, resilience, and nutrient uptake.

Potassium is one of the best things to feed grass to improve overall health, strength, and resilience. 

It’s wise for all of us to make regular applications of potassium to have the healthiest lawn possible, as it plays a critical role in having a healthier lawn. 

Let’s dive into precisely what potassium does and how it helps grass. 

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Potassium is great for grass; learn more about why.

What Potassium Does For Grass

Potassium is found in many fertilizers we see at our local lawn and garden store. 

It is part of the NPK ratio used to explain the nitrogen, phosphorus, and potassium concentrations in the fertilizer. 

Potassium plays a vital role in overall plant health. 

It is also celebrated for its ability to increase the resilience of grass, especially over the dormant winter season. 

Many lawn care enthusiasts find potassium to be a vital part of their winterization routine to ensure a healthy and robust growth period in the spring. 

Potassium helps to increase the uptake of water and nutrients by plants. 

This is especially advantageous as it often leads to less frequent watering. 

The plant doesn’t need as much watering because it adequately absorbs the water, which helps decrease the grass’s susceptibility to drought. 

This increased uptake of water and nutrients also helps to strengthen plants and grasses overall. 

Often this leads to increased resilience against: 

  • Pests
  • Disease 
  • Drought
  • Extreme Temperatures
  • Stress 

The increased resilience and strength from potassium is its biggest selling point. 

Potassium also helps to improve the health and strength of cell walls. 

This makes the grass stronger and more resilient. 

We recommend an application in the early spring and the fall. 

Feeding potassium to your grass at the biggest and end of the growing season ensures your grass is strong enough to withstand the harsh heat of summer as well as the freezing temperatures of winter. 

Potassium And Plant Health

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Potassium helps overall plant health.

Potassium is vital for overall plant health and a key nutrient in many fertilizers. 

Lack of potassium often leads to weak and yellowing grass. 

Not only is yellowing grass unattractive, but it also indicates poor plant health. 

Luckily, potassium will fix this problem. 

Ensuring your lawn has enough potassium ensures it withstands the wear and tear of outdoor summer activities. 

It will also ensure your grass is ready and able to withstand a summer drought or heatwave. 

We all want a lush, dense, and deep green lawn to be the envy of the neighborhood. 

The type of grass we want requires healthy and strong grass. 

This means we have to set our grass up for success with proper maintenance and care. 

Fertilization is one of the most important ways to improve and sustain healthy grass and a thriving lawn. 

It is also important to regularly mow, water, and aerate our lawns to ensure our fertilizer and potassium applications are not in vain. 

Root Development

One way potassium improves plant health is through root development. 

Potassium during the early growing season is vital for proper root growth. 

Potassium helps young and new plants establish their roots and is vital for establishing a new lawn. 

Roots are an integral part of all plants, including the grass on your lawn. 

They are responsible for absorbing nutrients and water into the plant, distributed and used to grow strong. 

Strengthens Cell Walls

Strong cells make vigorous plants, and potassium is key for improving the strength of cell walls in plants. 

Thicker cell walls make grass hardier and more durable. 

This is especially important for those living in climates with extreme temperatures. 

It is also essential for those of us with kids and pets. 

If your lawn experiences a lot of wear and tear from children and pets, you’ll want your grass to be as strong as possible, and potassium is critical. 

Just like with humans, grass health and beauty start on the inside. 

Having stronger cell walls helps our grass be strong and resilient. 

When our grass is strong from the inside out, it shows all the signs of beauty and health, including the deep green color and a thick, carpet-like feel. 

Improves Disease And Stress Resistance

Weak grass is incredibly susceptible to disease, fungi, and stress. 

Disease and fungus thrive on weak plants incapable of fending them off. 

If your lawn and grass are strong, you give it a much better chance at fighting off potential diseases and fungal infections. 

While we don’t generally think of grass being able to get stressed, there are many things capable of overstressing our lawns. 

Overstressed lawns are often weak, yellowing, and patchy. 

Grass experiences drought stress and stress from extreme temperatures, nutrient imbalances, and heavy foot traffic. 

Many of the stressors our lawn experiences are out of control, so it’s beneficial to prepare our lawns for any extreme swings in temperature or water supply. 

Helps With Nutrient Absorption 

If you’ve ever had a particularly stubborn lawn, you know how frustrating it is. 

Sometimes it seems like our lawns just aren’t absorbing everything we give it. 

In these cases, potassium may be the answer. 

Potassium is an essential nutrient helpful in improving the efficiency of the nutrient absorption process in plants.

By ensuring our grass and lawns have adequate potassium levels, we provide our lawns are absorbing all the vital nutrients for growth and strength. 

Potassium is included in many fertilizer products in conjunction with other nutrients and compounds. 

Since it helps with overall nutrient absorption, it helps to include it in various fertilizers to make sure the plants absorb everything efficiently. 

How Potassium Helps With Winterizing Your Lawn

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Potassium will help your lawn get ready for winter.

Chances are if you’ve seen potassium in the store, it’s marketed as an excellent way to winterize your lawn. 

Many lawn care enthusiasts credit potassium with its strong and dense spring growth. 

Sufficiently supplying your lawn with potassium will have you as the envy of your neighbors. 

Potassium plays a crucial role in helping to winterize your lawn by strengthening the grass. 

Most grass species go dormant during the colder winter months and come back in the spring full force. 

When your grass and lawn enter the dormant state, it is significantly more susceptible to damage by many sources. 

To assure your lawn is strong enough to make it through the winter, you need to give it all the nutrients it needs, and this includes potassium. 

Many people who do not fertilize with potassium before the freezing temperatures of winter find they need to reseed once spring hits. 

Their lawns come in patchy, yellow, and weak. 

To avoid dealing with pesky bald patches on your lawn, make sure you administer the correct frequency of potassium applications for your lawn. 

This way, you’ll experience a healthy lawn from the start without having to reseed and fill in patches which is often an unpleasant chore. 

When To Apply Potassium

When it comes to applying fertilizer, timing is just as important as picking the right product for your grass and lawn. 

You don’t want to risk wasting your money or time through improper application. 

It’s essential to consider a few factors when applying potassium. 

Many fertilizers pack a large percentage of nitrogen in addition to potassium. 

So if you apply a spring fertilizer, chances are you already give your lawn plenty of potassium. 

If your lawn and grass look healthy and green, you likely won’t need additional potassium. 

If your lawn still yellows with your current fertilizer, potassium may help rejuvenate your lawn and support greener grass. 

We recommend making applications of potassium in the early spring, midsummer, and early fall for optimal growth and a healthier lawn. 

Soil Test

Before you apply any fertilizer to grass and your lawn, we highly recommend getting a soil test done. 

Soil tests are conducted by assessing soil samples for their compositional makeup. 

This is incredibly helpful in determining the overall health of your soil. 

Sometimes soil tests reveal heavy metals and pollutants. 

Most of the time, your soil test shows which nutrients it lacks. 

It also shows which nutrients you don’t need to supplement. 

Since most fertilizers supply nitrogen, phosphorus, and potassium, you’ll want to pay special attention to those levels in your soil test results. 

If your test results come back and show high levels of any of those big three nutrients, you’ll get a better idea of how much you need to supplement and how often you should fertilize your soil.   

While it is hard to over-fertilize your lawn with potassium, you still don’t want to waste your time or money. 

Suppose your grass is yellowing, but your soil composition contains adequate potassium levels. 

In that case, there is likely a different underlying problem causing this to happen, and adding potassium won’t necessarily fix the issue. 

Grass Type

Another critical factor to consider when applying potassium or any other fertilizer to your lawn is the type of grass growing. 

Different species of grass have different needs for fertilization and care. 

It is essential to familiarize yourself with the type of grass seed you planted to make sure you are giving it the optimal care possible. 

Early Spring

Early spring applications give your lawn an added boost during the beginning of the growing season. 

It also helps to build up strength and resilience before the scorching temperatures of summer arrive. 


A midsummer application of potassium helps replenish any lost nutrients. 

In the heat of summer, our grass is working overtime to stay hydrated. 

This requires more frequent watering, quickly absorbed and evaporated from the plants. 

During this time of year, many lawn care enthusiasts notice their grass begin to show signs of decreased strength. 

Usually, this occurs through the yellowing of grass. 

Giving your grass an added boost of potassium during this time helps replenish our plants. 

Early Fall

Supplying your lawn with potassium during the early fall is arguably the most critical application of the year. 

Most lawns suffer significant damage during the winter months. 

The grass is very resilient, but it still benefits from a little help. 

Winter causes grass to weaken and die. 

Strengthening your lawn during the fall will help decrease the level and intensity of damage caused during the winter. 

Where Does Potassium Come From?

Potassium is a naturally occurring element found in many different things. 

Most of the commercial potassium available online and in stores is mined. 

It is mined as a salt called potash. 

Potash is water-soluble potassium found in various salts. 

Many different types of soils have potash naturally occurring. 

However, it is often in an accessible form. 

Naturally occurring potash is often unavailable or accessible for plants to absorb and use. 

For this reason, regular fertilization with accessible potassium is incredibly beneficial for our lawns. 

There are also many naturally occurring sources of potassium like: 

  • Compost 
  • Seaweed 
  • Wood Ash
  • Mulched Leaves 

Check out our list of ways to get potassium in your grass.

Granular Potassium

Many large-scale operations or homeowners with large properties use granular potassium to feed their lawns and grasses. 

Using granular potassium requires a push spreader or broadcast spreader. 

Push spreaders are much more common for residential and small-scale properties, while broadcast spreaders are almost exclusively used for very large-scale properties with lots of ground to cover. 

Granular potassium is a great way to administer potassium into your soil in a form readily accessible for our grasses to absorb. 

It is advantageous to time your application of granular potassium with a big rainstorm. 

If there is no rain in the forecast, you must deeply water your lawn to promote proper potassium absorption into the soil. 

Otherwise, your grass won’t be able to access it. 

Liquid Potassium

Most homeowners use liquid potassium and fertilizers, especially if their hoses reach their whole lawn. 

Many liquid potassium products are easily attached to the hose for easy applications. 

Others come in concentrated liquids. 

Concentrated solutions need to be properly diluted before applying to the lawn. 

While excess potassium doesn’t necessarily harm plants, it is still wasteful. 

One of the best benefits of using liquid potassium over granular potassium is the ease of application and absorption. 

Unlike granular potassium, liquid varieties already have water included. 

This makes it much easier for the soil to absorb potassium. 

Also, you skip the step of additional watering, and you don’t need to time it with the rain. 

Natural Alternatives

Some people worry about the negative effects of run-off with the lawn care products they use. 

Luckily, potassium is not considered harmful to the environment or wildlife except in exceedingly high concentrations. 

These harmful levels are not used in most lawn maintenance situations, so there is little to worry about. 

If you are unsure about run-off from commercial potassium products, there are plenty of natural alternatives. 

Potassium naturally occurs in organic material. 

It is straightforward to find a natural source of potassium for your lawn. 

This way, you enjoy all the strengthening and resilience-building benefits of potassium for your lawn without worrying about negatively impacting water sources or wildlife around you. 


If you keep a compost bin or system on your property, you have a great source of potassium readily at your disposal. 

Many lawn and garden stores sell compost as well. 

Compost contains high amounts of potassium from various fruits and vegetables. 

In particular, bananas produce a lot of potassium in the compost bin. 

There is an easy and cheap way to make a potassium-packed compost tea for your lawn. 

Simply add banana peels and compost to water and allow it to steep for 1-2 weeks. 

Once the water has adequately absorbed the potassium from your compost and banana peels, you’ll have an all-natural and organic potassium fertilizer for your plants and lawn. 

Leaves And Sticks

Another free source of potassium is broken down leaves and sticks. 

When these natural materials biodegrade, they release vital nutrients for the soil and grass, including potassium. 

Simply put the leaves or sticks through a mulcher and spread them throughout the lawn. 

As the leaves and sticks continue to break down, they release potassium and a host of other beneficial nutrients for soil and grass health. 

While we generally work very hard to rid our lawns of leaves and sticks, they have undeniable soil and plant health benefits. 

Consider leaving some on the grass to allow your little patch of ground to thrive with naturally occurring nutrients from your environment. 


Many seaweed and kelp meal products pack a lot of potassium. 

You may have noticed various products in your local lawn and garden store containing seaweed and kelp. 

This is because they are packed with incredible nutrients for plants. 

Consider using this natural source of potassium if organic fertilizer is essential to you. 

Mined potassium, or potash, has its drawbacks as far as environmental degradation goes. 

Using naturally occurring and quickly renewable sources of potassium is a great way to be environmentally conscious in your lawn care routine.