Will Ammonia Kill Grass? – A Complete Guide On Ammonia

Ammonia is one of the top choices to kill weeds on the lawn. As strong as the odour, ammonia is very effective in eliminating plants with very little effort. But it has some downside too, as it is a non-selective chemical which raises the question – Will ammonia also kill grass?

Yes, ammonia is a non-selective chemical which means it doesn’t only kill weeds but all the plants it reaches. When it is applied to a plant, ammonia gets absorbed into the plant and starts attacking the cells, and slowly kills it. Ammonia applied to the soil will get into the roots of the plant and eliminate it with no chance of regrowth.

Now you know that ammonia can kill grass, but ammonia also helps the grass to grow. How is it possible? Let’s take a look at what ammonia is and the different types of ammonia that helps or restrict grass growth. 

Will Ammonia Kill Grass? - A Complete Guide On Ammonia


Ammonia is a chemical that is used in a lot of different ways and comes in a lot of different types. There are several types of ammonia, some help the plants to grow healthy but some kill the plant from the root if it comes into contact. Choosing the right kind of ammonia for the work becomes important as if choosing the wrong one, can have a different effect on the lawn. 

Let’s take a look at the most common types of ammonia used in the lawn and their effects:

  • Ammonium Hydroxide(NH4OH) – Ammonium hydroxide also known as household ammonia which is found in many household cleaners, such as soap or floor cleaners, etc This chemical is very effective in killing plants as it is made up for cleaning purposes and don’t have enough nitrogen to help the grass or plants to grow. Chemical concentration on different ammonia products can also vary, making it very difficult to see what effect it will have in the lawn or garden killing weeds or unwanted plants making it very easy to destroy the whole area.
  • Ammonium Nitrate(NH4NO3) – Ammonium nitrate is the one that provides nitrogen to the plant. It is one of the most commonly found in synthetic fertilizers which are used in the fall and winter seasons. Ammonium nitrate releases the nitrogen in the soil very quickly making it very helpful for an established lawn but it is not suitable for new or unhealthy lawn as excess or a high percentage of nitrogen can kill or burn new or weak grass. 
  • Ammonium sulfate((NH4)2SO4) – Ammonium sulfate is used in the lawn and garden to increase the acidity of the soil by lowering the pH level of the soil to grow acid-loving plants. It is not usually added in the commercial fertilizer as it is not helpful for the grass or normal plants and over-application can burn the grass. You need to be very careful when using ammonium sulfate as any amount of imperfection can ruin the lawn or garden.
  • Ammonium phosphate sulfate(H4NO8PS) – Ammonium phosphate sulfate(APS) is very helpful for the grass as it provides a slow release of nitrate as well as phosphorus to the soil, which is very useful for newly seeded lawn or unhealthy lawn as it is gentler than ammonium nitrate. The phosphorus helps the plants to develop deep roots and establish themselves in the soil making them healthy and capable to withstand drought and heat very easily. This compound is used in commercial starter fertilizer as this type of compound is used in preparing the soil before the grass seeds are planted or the sod is laid out on the lawn.


Ammonia comes in different types so it depends on which type of ammonia you are using for your lawn. For example, ammonium nitrate helps the grass or plants to grow by helping in providing food but on the other hand, ammonium hydroxide can kill the whole plant very easily. So it depends on which type of ammonia you are using and for what purpose. 

There are more types of ammonia but all have different purposes so consider the types of ammonia you need for the lawn. If you want to kill the weed then ammonium hydroxide is good but if you want to boost the growth of the grass then you need to use ammonium nitrate. 


Yes, Ammonia can kill the grass as it is a non-selective chemical. Ammonium hydroxide or all also known as household ammonia can easily destroy your lawn. Household ammonia is used for deep cleaning which means it is a highly corrosive chemical and when applied neat into the lawn, it can immediately burn out the grass and other plants. 

The ammonia attacks the grass directly into the cell and slowly kills the whole plant. If ammonia gets into the soil, it gets absorbed by the roots of the grass and kills the entire root system which makes it impossible for the grass to regrow. It also blocks new seeds from germinating into the soil until ammonia is present in the soil. 


Yes, Ammonia (Ammonium hydroxide) is a very good weed killer as it is a non-selective chemical. But the downside is that ammonia (Ammonium hydroxide) can also kill other plants which come into contact. So if you are applying ammonia into a lawn or garden to kill the weeds, you need to take a lot of precautions as a little bit of excess ammonia can destroy the lawn or garden and can kill all the desirable plants or grasses. 

Ammonia (ammonium hydroxide) kills the weed as same as any other plant by seeping through their roots or by attacking the cells of the plant and killing the whole plant without any chance of regrowth which makes it a very effective weed killer if used appropriately. 


  • Crabgrass 
  • Dandelions 
  • Common ragweed
  • Hedge bindweed
  • Ground ivy 
  • Stinging nettle 


Using Ammonia (Ammonium hydroxide) to kill weeds is very easy and effective. You need to take proper precautions as Ammonia can be harmful and can cause irritation to the skin. Also, Ammonia is a non-selective chemical which means it will kill all the plant which comes into contact so applying it precisely only on the weeds is very important. 

  1. Prepare solution – First, make a proper solution of ammonia and water which is effective. Mix water and ammonia in the ratio of 1:2, which means one part water and two-part ammonia. If you want, you can add one tablespoon of soap so that the solution sticks to the weeds and is more effective. 
  1. Pour – Fill the solution into a spray bottle so that you can easily spray it only to the plants or weeds you want leaving the whole area or soil. Adjust the nozzle of the spray bottle precisely so that it results in spraying the only part of the area you are directing. 
  1. Spot test -Spot tests the solution into one or two weeds and see if the application is correct and the solution is not reaching other plants. 
  1. Spray – If everything seems alright then spray the solution to all the weeds or unwanted plants. 
  1. Repeat – Repeat the application up to two to three times to have the desired result and to make sure no unwanted plant is left behind or alive after the first or second application. 

Precaution – Whenever working with ammonia, wear garden gloves and mask and make sure the skin doesn’t come in contact with the chemical as it can cause irritation as well as harm your lungs and eyes.  

Can you spray ammonia on your grass?

There are two types of ammonia. Ammonium nitrate and ammonium hydroxide. The first gives the grass nutrients and the other kills the grass. So depends on what result you want you can spray ammonia to the grass. If you want the lawn healthy and thick then spray ammonium nitrate in the lawn. Normal ammonia which every household has will burn the grass. 

How long does it take for ammonia to kill grass?

Ammonia starts killing the plant immediately after the application and kills the grass in one to two days and also dries up the roots of the plant. If the ammonia is not applied correctly then it will take longer to kill the grass. If it is taking time then you can apply ammonia one or two times more.