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Can Lawn Fertilizer Harm Dogs?

Dogs are notorious chewers, and they will chew up grass on your lawn as well. However, allowing your dog to play on your lawn could have serious health consequences. Especially after you have applied fertilizer recently. 

Can lawn fertilizer harm dogs?

There is no doubt that fertilizer is helpful, but does fertilizer negatively affect dogs? Or Can lawn fertilizer harm dogs? 

Fertilizers with excessive levels of nitrogen, phosphorus, and potassium can cause many problems in dogs and cats. 

In this article, we will discuss some potential garden dangers that can harm your dog.

Can lawn fertilizer harm dogs?

If you’ve got a nice big lawn and your dog’s getting out a lot more in the sunshine, you might be tempted to let them run around on their own — but could the chemical fertilizers and pesticides you recently applied to your lawn be causing harm to your pet?

Lawn fertilizers can be harmful to dogs, but they’re not always deadly. If your dog consumes a large amount of fertilizer, he might get sick or even die. Large amounts of fertilizer can also cause burns.

It may cause vomiting, diarrhea, or both. He may also develop stomach cramps and bloat — an emergency condition where his stomach fills with gas so quickly that it causes pain and potentially death if not treated immediately.

What fertilizers are toxic to dogs?

What fertilizers are toxic to dogs?

The two main ingredients in lawn fertilizers that can be dangerous for dogs are phosphorus and nitrogen. 

Phosphorus is an element that is essential for growth in plants. Nitrogen is necessary for plants to produce chlorophyll and make food from carbon dioxide and water. These minerals are often added to lawn fertilizers to help the grass grow better and faster.

Among the other ingredients often found in fertilizers are:

  • Iron: Too much iron can be toxic and cause damage to internal organs and brain cells.
  • Disulfoton (responsible for seizures and pancreatitis): Disulfoton is a pesticide that’s used on corn crops and other types of grain. It can also be found in some fertilizers used to treat lawns.
  • Copper: Too much copper can lead to liver damage, kidney failure, seizures, and even death in dogs.
  • Zinc: Zinc toxicity can lead to vomiting, diarrhea, lethargy, and loss of appetite in dogs.

Is organic fertilizer toxic to dogs?

Is organic fertilizer toxic to dogs?

Organic fertilizers are derived from animal and plant sources, including blood meal, bone meal, cottonseed meal, and manure. Organic fertilizer is a great way to improve the health of your lawn and garden, but it does come with some risks. 

Organic fertilizers often contain nutrients that are less stable than synthetic fertilizers. When these fertilizers break down, they can produce toxic gases that are harmful to both people and pets.

While organic fertilizers are safe for your lawn and plants when used properly, they can cause health problems if they’re ingested by pets. 

When organic fertilizers are ingested in high quantities, pets may experience vomiting, diarrhea, and pancreatic inflammation. 

What about commercial fertilizer?

What about commercial fertilizers, are they harmful to my dog? Can lawn fertilizer harm dogs?

Commercial fertilizers are designed to make plants grow faster and stronger, but they don’t necessarily improve the plant’s nutritional value. These products usually contain very high levels of nitrogen, phosphorous, and potassium. Many commercial fertilizers also contain high levels of salt.

If your pet consumes commercial lawn fertilizer, it could cause some serious health issues like abdominal pain, excessive drooling, vomiting, discolored gums, bowel obstruction, difficulty breathing, cardiac arrest, and even inflammation of the liver and pancreas. 

Therefore, it’s very important to keep your pets off any area of the lawn that has been recently fertilized.

How much fertilizer is toxic to dogs?

The amount of fertilizer that can cause poisoning depends on the type of fertilizer and the amount ingested. 

In general, the smaller the dog, the less it can tolerate before it becomes toxic. For example, a 10-pound (4.5 kg) dog can tolerate approximately 0.5 g/kg of nitrogen-based fertilizer or 2 g/kg of phosphorus-based fertilizer.

One teaspoon of fertilizer contains about 1 gram (0.035 oz) of nitrogen. Therefore, if your dog consumes a teaspoon or less nitrogen-based fertilizer, it is unlikely that he will be affected by it unless he eats more than one teaspoon in one sitting. 

If your dog ingests more than one teaspoon of nitrogen-based fertilizer at once or multiple teaspoons over time, then you should seek veterinary care immediately because he could develop serious health problems from ingesting too much nitrogen-based fertilizer.

Can dogs eat grass that has been fertilized?

Can dogs eat grass that has been fertilized?

Grass that has been fertilized is safe for dogs to eat most of the time, but it can be a choking hazard and cause intestinal blockage if ingested in large amounts. 

If the dog has a history of small intestinal blockage or other gastrointestinal problems, it would be best to avoid feeding him grass altogether.

How long after lawn treatment is it safe for pets?

Depending on the weather—rainy weather means quicker absorption—allow at least 1-2 days for the fertilizer to absorb into your lawn before letting your pets back on it.

What should I do if my dog eats fertilizer?

The ASPCA Animal Poison Control Center (APCC) receives thousands of calls each year about pets that have ingested potentially poisonous substances. 

Exposure to fertilizers should be considered an emergency, as there have been cases where dogs have died after ingesting large amounts of fertilizer.

First, it’s important to stay calm. Dogs can recover from many types of poisoning if treated promptly, so don’t panic.

Contact your vet immediately with the name of the fertilizer (it might be identified on the label) so that your dog can receive the proper treatment. If you can’t reach a veterinarian, call your local animal emergency hospital.


While there is some controversy about “can lawn fertilizers harm dogs,” one thing that is clear is that ingesting any fertilizer in large amounts can be extremely dangerous. I would advise keeping your dog away from fertilizer and lawn treatments at all times in the future.

Ian richardson

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