Is Fertilizer Bad for Dogs?

dog sniffing on grass

Garden fertilizers can harm your dog when ingested in high amounts or mixed with toxic substances like pesticides. In most cases, pets only suffer mild gastrointestinal symptoms like vomiting and diarrhea, but if pesticides get involved, the symptoms can become more severe. 

Read this guide to learn which fertilizers are bad for dogs, how to store and use lawn fertilizers properly to keep your dog safe, and what to do in case of accidental ingestion.

What are fertilizers

Fertilizers are natural or synthetic products containing chemicals that support plant growth. Nitrogen, phosphorus, and potassium (potash) — or N, P, and K — are essential nutrients plants need to thrive and are the main ingredients in commercial fertilizers.

Fertilizers contain nitrogen, phosphorus, and potash in different amounts, which are written on the label as the N-P-K ratio. For example, a product with 10-0-4 NPK has 10 parts nitrogen, zero phosphorus, and four parts potassium. 

Complex formulas also have micronutrients such as boron, calcium, chlorine, copper, iodine, iron, magnesium, manganese, molybdenum, nickel, and zinc.

Man's arms holding soil in one hand and fertilizer in the other
evgenyb | Canva Pro | License

Fertilizers can cause health issues in dogs for various reasons:

  • Products rich in nitrogen, phosphorus, or potassium are difficult to digest and cause gastrointestinal issues if ingested. Some nitrogen sources, like urea and anhydrous ammonia, are more harmful than others. Anhydrous ammonia is primarily used in farm products and less in residential applications.
  • Some ingredients, like iron, can cause toxicity if ingested in high amounts.
  • Fertilizers mixed with pesticides can attack the nervous system and your dog’s organs (liver, kidney, pancreas).
  • Some organic fertilizers (aka meals) can cause pancreatitis and intestinal obstruction. 
  • Tasty fertilizers can lead dogs to eat poisonous plants or bulbs from your garden.

Licking their paws and fur after playing in a treated area will rarely cause more than mild symptoms. Munching sprayed grass and fertilizer granules from the soil also has a low risk unless toxic pesticides are involved. The main cause of dogs getting into the emergency room with severe fertilizer poisoning is direct ingestion from the fertilizer container or spreader.

Types of fertilizers that are dangerous for dogs

As a good rule of thumb, dog owners should not expose their pets to fertilizers — or any other garden products. Direct exposure during application can lead to skin burns, rashes, and breathing problems, especially when spraying liquid fertilizers. Keep pets and kids inside when applying any landscaping fertilizer.

This being said, some fertilizers are more dangerous for dogs than others.

Organic fertilizers with animal scent

Hands holding fertilizer
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Surprisingly, part of the danger comes from a few organic fertilizers we all consider natural and safe. If you fertilize with organic products, keep your dog away from:

  • Bone meal
  • Fish meal
  • Blood meal
  • Chicken feather meal

These organic fertilizers, otherwise safe for the environment, are made from animal leftovers and thus smell pretty delicious to dogs. If improperly stored and supervised during use, your furry friend will likely gobble them up and get sick:

  • Consuming large amounts of bone meal can lead to intestinal obstruction — it forms a large cement-like ball in the stomach that often requires surgery to remove. 
  • Blood meal ingestion can cause vomiting and diarrhea and, in large amounts, can trigger pancreatitis (inflammation of the pancreas). The risk of iron toxicity also exists if the product is enriched with iron.
  • Fish and feather meals are not toxic to dogs, but when consumed in high amounts, they’ll also hurt their stomach and provoke diarrhea and vomiting.

Dogs can sniff their treats even in small amounts, so consider any fertilizer that uses these organic ingredients a risk to their health. The most dangerous are mixtures containing toxic substances like pesticides, herbicides, or fungicides.

How do you keep your dog safe from fertilizer meals? 

  • After spreading, cover the fertilizer with topsoil or a layer of mulch to hide the scent. Watering the area reduces the fertilizer concentration.
  • Keep the dog away from the area for the duration indicated on the package.
  • Never combine them at home with insecticides, herbicides, or fungicides.
  • Replace them with vegetable alternatives like kelp meal, alfalfa meal, or seed meal.

Fertilizers with pesticides or herbicides

This category includes commercial fertilizers mixed with herbicides (labeled as weed and feed) and products that include insecticides or fungicides. It also refers to homeowners mixing regular fertilizer with pesticides or herbicides to simplify application.

Most chemical insecticides can harm dogs if ingested, and some, if inhaled or in contact with the skin, but the most dangerous to watch for are organophosphates.

Organophosphates are toxic chemicals that attack the muscles and nervous system and can be lethal to pets without treatment. Among the most toxic examples are pyrethroids and disulfoton. Disulfoton is often used to protect roses from pests and is sometimes mixed with bone meal, which makes it dangerously attractive to dogs. About one teaspoon of fertilizer with 1% disulfoton can kill a large dog.

Herbicides such as glyphosate and 2,4-D are also toxic to dogs if ingested. 

Cocoa mulch with its chocolate flavor

plant planted in cocoa mulch
Leslie Seaton from Seattle, WA, USA | Wikimedia Commons | CC BY 2.0

Cocoa bean mulch is both an ornamental soil cover and an effective fertilizer. It has a soft chocolate aroma, looks good, and is rich in nutrients that slowly release into the soil. All these qualities make it a luxury choice for flower gardens and classy landscaping projects. However, cocoa mulch is toxic to dogs and cats. 

Cocoa mulch is made of the shells and hulls of the cocoa bean and contains theobromine, the same substance that causes chocolate poisoning if you feed your dog chocolate. 

Because dogs love the chocolate smell, which is said to last at least a month after spreading the mulch, they are tempted to eat it and expose themselves to chocolate toxicity. The most common symptoms are vomiting and muscle tremors, but high heart rate, hyperactivity, and diarrhea also can appear.

How do you keep your dog safe from cocoa mulch? 

  • Keep cocoa mulch in closed containers and safe locations, away from your dog’s reach.
  • Apply only in areas where dogs can’t enter, such as flower beds surrounded by fences or the backyard/front yard when separated by a gate.
  • Don’t use it if you have dogs. Instead, go for shredded bark, hay, or other less palatable and toxic mulch options.

Fertilizers with iron

Complex fertilizers have added micronutrients such as iron, calcium, magnesium, copper, zinc, and manganese. While most are present in tiny amounts and are not likely to pose problems, iron can lead to iron toxicity if a large quantity is ingested. 

Common symptoms of iron toxicosis in dogs are vomiting, diarrhea, and anorexia.

What should you do about iron-rich fertilizers?

  • Store the fertilizer safely in a garage and closed containers.
  • Keep the dog out of the yard during application and 47 hours afterward.

Moldy fertilizers

If ingested, moldy fertilizer, food, plant material, or compost can be toxic to your dog. They contain tremorgenic mycotoxins that make dogs ill quickly, and symptoms usually appear within an hour after ingestion. Common signs of mold toxicity include hyperactivity, tremors, vomiting, high body temperature, and convulsions in severe cases.

To prevent mold, keep the fertilizer containers closed and stored in a dry space. Packages you keep open can harbor mold even if it’s invisible to the naked eye.

What are pet-friendly fertilizers?

It’s unsafe for your dog to ingest any type of fertilizer, even pet-friendly fertilizers. However, pet-friendly fertilizers tend to contain less toxic additives than regular fertilizers. This means your dog is safer to run and play on your lawn after using them, and ingestion only causes mild symptoms.

That being said, don’t take the pet-friendly label for granted. Check the list of ingredients, follow the application instructions, and keep your dog out of the treated area for as long as the package says to.

Symptoms of fertilizer poisoning

owner petting a sick dog
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If your dog ingests fertilizer their symptoms can start with gastrointestinal irritation, vomiting, diarrhea, lethargy, hypersalivation, and abdominal pain. Regular NPK fertilizer typically causes mild symptoms, unless a large amount of fertilizer is ingested.

If a fertilizer contains toxic additives, gastrointestinal symptoms are only the start. The list of clinical signs also includes:

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

What should you do if your dog eats fertilizer?

First, try to find out the fertilizer’s ingredients and the amount your dog ate. The fertilizer package can help you check for toxic chemicals. 

Pro tip: Take photos of your garden chemicals packages with your phone. This way, you’ll always have them if you must check the ingredients.

Call your veterinarian to decide if you can treat the problem at home or if you must take your dog to the vet. You also can contact the Pet Poison Helpline or the ASPCA Animal Poison Control Center for help. 

In some cases, the vet can recommend stimulating vomiting at home, but don’t try this unless recommended by a specialist. They’ll explain exactly what products to use and in what amount, depending on your dog’s weight.

What to expect if you have to take your dog to the vet:

  • A thorough physical examination 
  • Meds to induce vomiting if toxic chemicals need to be flushed out of your dog’s stomach
  • Meds to stop vomiting if it’s severe
  • An X-ray to check for obstruction — common when bone meal is the ingested fertilizer
  • IVs to hydrate the dog and help flush out toxins

How to keep your dog safe from fertilizer poisoning

Dog on lawn

Dog owners can use fertilizers on their lawns and gardens if they follow a few safety rules, such as:

  • Choose pet-friendly fertilizers if possible. They’re made with less toxic chemicals. 
  • Don’t mix pesticides (insecticides, herbicides, or fungicides) with your fertilizer, especially if your dog is attracted to it.
  • Keep your lawn fertilizers and other garden products safe, stored in closed containers in a locked space.
  • Remove dog toys, bedding, food, and water bowls if they are in the treated area.
  • Follow the application instructions correctly. 
  • Use the right concentration if you’re using a liquid fertilizer requiring dilution. Properly diluted fertilizers are less dangerous.
  • Don’t leave a filled spreader or an open fertilizer bag unattended at any time if the dog is still outside.
  • Keep your furry friend away from the treated area during application and for at least 48 hours after or as long as the fertilizer package indicates.
  • If you must let your dog out sooner after an application, use a leash to walk them and avoid the area.

What if Fido sneaks out and walks on your lawn after a fertilizer application? Give your dog a bath to remove all traces of fertilizer from its fur and paws. Only a few fertilizers, mainly those containing pesticides, are so dangerous that a dog can harm itself only by running across the yard, getting product on its body, and licking its fur and paws. 

New to dog parenting? Read more about lawn care with a dog in your yard from our guide 10 Lawn Care Tips for Dog Owners.

FAQ about fertilizers and dogs

Is manure a pet-friendly fertilizer?

Manure can cause gastrointestinal distress if ingested in large amounts, but this rarely happens. Keep it away from your dog if it shows a particular attraction to it. Most times you can use it on your lawn and yard without problems.

Is nitrogen fertilizer safe for dogs?

Fertilizers high in nitrogen can cause vomiting and diarrhea if ingested in large amounts (directly from the bag) but are unlikely to lead to more severe symptoms.

Why is my dog obsessed with fertilizer?

If your dog has a fertilizer obsession, your fertilizer probably contains ingredients appealing to them, such as bone meal, blood meal, or cocoa mulch. To prevent accidental ingestion, keep the fertilizer safe in a closed container placed in a space where the dog doesn’t have access. You also can change the fertilizer with one that uses vegetable nutrient sources.

Get a lawn care pro’s help!

If your dog ingested fertilizers, call a vet immediately! A lawn care pro can’t help you with that, but they can surely support you in choosing safe fertilizers and applying them correctly on your lawn. Find a pet-wise lawn care company with Lawn Love and ensure your yard is thriving and a safe green heaven for your pets to play in!

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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.