Is Fertilizer Bad for Dogs?

dog sitting on grass with an overlay of a fertilizing garden image

Dogs love running through tall, lush grass, but the fertilizers that keep the lawn green and thick might threaten their health. Lawn fertilizers are bad for dogs if ingested, especially when they contain toxic additives. Surprisingly, some organic, natural products can do lots of harm, too.

Read this guide to learn what makes garden fertilizers toxic for dogs, which are the most dangerous products, and how to keep your pet safe while adequately caring for your plants. 

What Makes Fertilizers Bad for Dogs

Ingested Amount

Garden fertilizers contain various amounts of nitrogen, phosphorus, and potassium (potash), as indicated by the N-P-K ratio (the three numbers you see on the fertilizer label, such as 10-0-4). Some also have trace minerals, such as boron, cobalt, copper, iron, manganese, or zinc, and toxic additives, like pesticides, that can cause health issues if ingested.

Most fertilizers are not harmful or cause only mild symptoms when dogs consume small amounts while chewing on fertilized grass or licking their paws after a walk on the lawn. 

However, more severe health problems typically arise when dogs break into the fertilizer bag or spreader and munch up granules directly from the source. In this case, gastrointestinal symptoms like vomiting and diarrhea almost always appear because the body can’t handle the high nitrogen content.

What’s a dangerous amount of fertilizer for your dog? The danger level depends on your fertilizer composition. For example, a teaspoon of fertilizer containing 1% disulfoton can be lethal for a 55-pound dog. By comparison, a teaspoon of regular NPK fertilizer without harmful additives can pass through the body of a large dog without any symptoms or just mild diarrhea and vomiting. 

Your dog’s size also matters. The same amount of ingested fertilizer can lead to mild symptoms in a large dog and severe ones in a puppy or a small breed. 

Toxic Additives

fertilizer in a gardener hand
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Fertilizers are more dangerous to dogs when toxic additives are included. Look carefully on your fertilizer’s label, especially if it’s a weed and feed, for the following ingredients that come with a higher risk of toxicity:

  • Iron: Ingesting iron in high amounts can lead to iron poisoning. Symptoms start with diarrhea and vomiting in the first six hours after ingestion. Though rare, iron toxicity can lead to coma when large amounts are ingested. 
  • Disulfoton: Disulfoton is an insecticide sometimes added to granular rose fertilizers and is extremely dangerous for dogs and cats. One single teaspoon with 1% disulfoton can kill a 55-pound dog. Symptoms include increased salivation, tear production, vomiting, rapid breathing, tremors, increased heart rate, and seizures. 
  • Pesticides: Organophosphates, carbamate, and some pyrethroids are among the most toxic to pets. They attack the nervous system and can lead to seizures and coma. 
  • Herbicides: Glyphosate, 2,4-dichlorophenoxyacetic acid (2,4-D), and 4-chloro-2-methylphenoxy propionic acid (MCPP) are three weed killers to keep away from your dog. Toxicity symptoms range from vomiting and diarrhea to ataxia and tremors.
  • Urea: Often used as a nitrogen source in residential-use fertilizers, urea can be toxic for dogs. Ingested in small amounts leads to gastrointestinal symptoms. Large ingestions can lead to methemoglobinemia (hemoglobin can no longer carry enough oxygen to organs and tissues).

Attractive Smells 

Surprisingly, some organic fertilizers considered safe for the environment can be hazardous to pets because of their attractive aroma. Bone meal, fish meal, blood meal, and feather meal are popular organic fertilizers made of animal byproducts from the meatpacking or farming industry. 

For us, they smell bad, but for your dog, they smell like delicious food. Such products are more likely to drive pets to dig into fertilizer packages and eat large quantities. They might even eat them from the soil if you allow access in the yard soon after spreading. 

In small amounts, they cause gastrointestinal irritation, diarrhea, and vomiting. In large quantities, they can obstruct the intestines and require surgical intervention. Blood meal ingestion also can cause pancreatitis (e.g., inflammation of the pancreas).

Warning! Mixing such fertilizers with pesticides or herbicides increases the risk of ingestion and severe toxicity. Your dog also might be tempted to eat poisonous plants or bulbs that are covered in an animal-derived fertilizer.

Moldy Fertilizer

Any type of solid fertilizer can become toxic to your dog if it is moldy. Mold contains tremorgenic mycotoxins that trigger symptoms within an hour after ingestion. Common clinical signs of mold toxicity include:

  • Hyperactivity
  • Weakness
  • Tremors
  • Vomiting
  • High body temperature
  • Convulsions in severe cases

Keep the fertilizer containers closed and stored in a dry, ventilated space to prevent mold. Packages kept open can be infested even if mold is invisible to the naked eye.

Type of Fertilizer

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Commercial landscaping fertilizers come in two primary forms: liquid and granular. Neither category is 100% safe for pets, even if labeled “pet-friendly,” and should be appropriately stored where dogs and cats can’t reach it.

Once applied, liquid fertilizer is absorbed by plants and soil relatively fast. After it dries out, your lawn and garden are typically considered safe for pets. When you apply liquid fertilizer to potted plants, it can overflow at the pot’s base, where dogs can drink it. Keep pets away from freshly fertilized pots and wash the overflow.

Granular fertilizers require water (rain or irrigation) to dissolve into the soil. Most experts recommend watering the lawn or garden and allowing the soil and fertilizer to dry out before letting the dog out for a walk. 

To always be on the safe side, wait 48 to 72 hours after a fertilizer application before allowing the dog back into your yard.

Cocoa Mulch

Most mulches you can buy at the local garden store are pet-safe and harmless for dogs since they’re not tempted to eat stuff like shredded bark or pine needles. Cocoa mulch is unique because it has a faint chocolate smell. Dogs love the smell and can’t wait to chew your chocolate mulch where you store it and where you spread it. 

This type of mulch is made from the hulls and shells of cocoa beans and contains theobromine. Theobromine causes chocolate poisoning if the dog ingests too much, causing mild to severe symptoms including:

  • Vomiting
  • Diarrhea
  • Not eating
  • Drooling
  • Dark red gums
  • Anxiety
  • Hyperactivity
  • High heart rate
  • Tremors
  • Seizures

What are Pet-Friendly Fertilizers?

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Pet-friendly fertilizers are organic, natural products free of toxic chemicals that could harm pets. Some brands have organic fertilizers marketed as safe for pets and kids, but you should always take this kind of statement with a grain of salt. To be on the safe side, choose fertilizers with the OMRI label that guarantees an organic product and watch for animal ingredients. 

Natural pet-friendly fertilizers to consider are:

  • Compost: Not so palatable for dogs that they would consider it good food, compost, with its balanced nutrients, makes an excellent fertilizer for your lawn and veggie garden. 
  • Seaweed (kelp meal): You can buy kelp meal as a liquid fertilizer to spray on your soil, as a powder, or in its natural form to use as mulch or dig into your topsoil. Unlike bone or blood meal, kelp meal is vegetarian and doesn’t attract dogs.
  • Grass clippings: The most straightforward and safest way to fertilize your lawn is to leave the grass clippings on it after mowing. 

How to Prevent Fertilizer Poisoning in Dogs

dog sniffing on grass
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  • Choose pet-friendly fertilizers with no pesticides among the ingredients.
  • Check the fertilizer ingredients on the package.
  • Store fertilizers and other garden chemicals in your garage or another locked space. 
  • Keep bags and containers closed, and don’t leave a filled spreader unattended.
  • Keep the dog safe and away from the lawn and garden during fertilizer application and when using other garden products.
  • If you apply bone meal, blood meal, or other animal-derived fertilizer, cover the area with topsoil or mulch and water the area to reduce the attractive smell and reduce concentration.
  • Don’t let the dog outside unsupervised if you just fertilized the garden.
  • Avoid using cocoa mulch in areas accessible to your dog. Limit the access by installing a fence or use a less risky type of mulch like shredded bark, dead leaves or grass clippings.

Dogs are playful and sometimes escape outside. What should a pet owner do if the dog walks on freshly fertilized grass? Bathe your dog to remove any chemicals on its fur and paws. If you suspect your dog ingested fertilizer, look for any signs of fertilizer toxicity and call the vet. 

Fertilizer Toxicity Symptoms in Dogs

The ingestion of regular NPK fertilizers typically leads to gastrointestinal irritation and connected clinical signs such as abdominal pain, vomiting, and diarrhea. Symptoms are often mild and not life-threatening. 

If the fertilizer contains toxic insecticides such as organophosphates, you can expect to see more severe symptoms reflecting health issues with the gastrointestinal and nervous system:

  • Drooling
  • Uncontrolled urination and defecation
  • Weakness
  • Inability to stand and walk
  • Disorientation or loss of balance
  • Irritation to the skin, eyes, or mucous membranes
  • High or low heart rates
  • Difficulty breathing (due to bronchoconstriction)
  • Tremors
  • Seizures
  • Coma 
  • Death

What Should You Do If Your Dog Eats Fertilizer?

a puppy dog playing in a green yard
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Determining what fertilizer your dog consumed and how much it ingested is critical. This speeds up diagnoses and treatment. Look for the fertilizer package or what’s left to check the ingredients. Figuring out if your dog ingested toxic additives like iron or disulfoton improves recovery chances.

Call your vet, the ASPCA Animal Poison Control Center, or the Pet Poison Helpline. They’ll tell you what to do next. Induce vomiting at home only if instructed to do so by a healthcare professional. 

What to expect at the vet:

  • Your dog will be examined.
  • An X-ray might be necessary to check for bowel obstruction if it ingested bone meal or blood meal.
  • In some cases, vomiting meds are administered to evacuate the toxic meal. 
  • Pumping the stomach or stomach lavage is used when vomiting meds don’t work.
  • If severe vomiting is a symptom, your dog will receive anti-vomiting meds.
  • An IV is sometimes administered to help the dog flush out the toxins in the body.

FAQ About Fertilizers and Their Danger for Dogs

What are the Most Dangerous Fertilizers for Dogs?

Fertilizers mixed with highly toxic insecticides such as organophosphates are the most dangerous for dogs. Bone meal and blood meal are also harmful when ingested in large amounts.

Why Is My Dog Obsessed with Fertilizer?

If your dog is obsessed with fertilizer and tries to get some in its mouth whenever it has a chance, your fertilizer may include appealing ingredients, such as:

  • Bone meal
  • Blood meal
  • Fish meal
  • Chicken feather meal
  • Cocoa mulch.

Can You Use Plant Fertilizer if You Have Dogs?

Yes, dog owners can use plant fertilizer. Keep the dog in the house while spreading fertilizer in your garden or lawn, and prevent them from entering the fertilized area for at least 48 hours after application. If you’re fertilizing indoor plants, ensure the dog can’t reach the pots or any water mixed with fertilizer that might leak out.

How Can a Lawn Care Pro Help?

Fertilizers can harm pets if chosen, stored, and applied incorrectly. A lawn care pro can help you pick the safest option, ensure proper application, and provide the recommended waiting time before your dog is allowed back into the fertilized space. 

Most lawn care pros use their fertilizers, so you won’t need to store yours and worry about Fido getting in the garage and turning it into lunch. Find a lawn care company with LawnStarter, put your fertilizer worries to rest, and enjoy your pet-safe lawn!

Main Image Credits
Dog: cmannphoto / Canva Pro / License
Fertilizer: Khaligo / Canva Pro / License

Sinziana Spiridon

Sinziana Spiridon

Sinziana Spiridon is an outdoorsy blog writer with a green thumb and a passion for organic gardening. When not writing about weeds, pests, soil, and growing plants, she's tending to her veggie garden and the lovely turf strip in her front yard.