Fertilizer and Mulch Dangers for Dogs

Getting ready to work in the garden this summer? Before you do so, make sure you know about potential garden dangers that can poison your dog. When in doubt, keep your pets inside while working with some of these common garden or yard additives.

During the spring and fall, homeowners often use fertilizers to spruce up their lawn. Fertilizers come in two types: granules or water-based products (that are directly sprayed onto the lawn).

Fertilizers look scary – they often are applied by lawn services with warning signs stating that children and pets should be kept off the grass for at least 72 hours. In actuality, fertilizers are generally pretty benign; in fact, they typically have a wide margin of safety depending on what type of product is used.

What’s in fertilizer?
Most lawn fertilizers contain natural elements (such as nitrogen, potash and phosphorous) — often represented by numbers such as 10:0:40. Thankfully, these elements are generally non-toxic. Fertilizers may also contain insecticides for killing grubs, snails, etc. that generally result in mild gastrointestinal signs (e.g., drooling, vomiting, diarrhea, etc.) when ingested directly from the bag.

If your dog eats some grass that had fertilizer applied to it, it rarely leads to serious poisoning; that said, more serious signs can be seen when the product is directly ingested (i.e., right out of the bag). If ingested directly from the bag, the results can include tremors and seizures.

To avoid any poisoning risk to your pet, follow the labeled instructions carefully and keep your pets inside while you apply these products to the lawn. To be safe, keep your pets off the lawn until the product is absorbed by the soil (e.g., when the product dries if it’s a spray-on product, or after it rains if it is a pelleted product). When appropriately applied or diluted, these chemicals typically wash into the soil after rainfall, resulting in low-risk to dogs.

The most important thing is to make sure it’s not a fertilizer that has more dangerous products in it – some may contain iron, which can result in iron poisoning, and less common types may contain very dangerous insecticides such as carbamates or organophosphates. Thankfully, the EPA has limited the availability of these latter, more dangerous types of products. Carbamates and organophosphates can result in more serious, life-threatening clinical signs such as:

  • Drooling
  • Vomiting
  • Severe lethargy/collapse
  • Diarrhea
  • Excessive tearing
  • Urination
  • Abnormal heart rates
  • Difficulty breathing (due to bronchoconstriction)
  • Tremors
  • Seizures
  • Death

Again, these more dangerous types are rarely seen on the market nowadays but, when in doubt, make sure to keep the garage door locked and these fertilizers out of reach!

Organic fertilizers (e.g., meals)
Surprisingly, the more dangerous types of fertilizers are organic fertilizers. Most pet owners want to use “safer” products around their pets, and so they often reach for something organic. Organic fertilizers are typically “natural” fertilizers that are leftover byproducts from the meatpacking or farming industry. Examples include:

  • Bone meal
  • Blood meal
  • Feather meal
  • Fish meal

These organic “meals” are widely utilized as soil amendment products, fertilizer components, or as deer, rabbit and wildlife repellants. These products are often highly palatable to dogs; they smell gross, but good to dogs, and so they may tempt a massive ingestion (e.g., dogs ingesting several pounds of bone meal directly out of the bag). Another danger? Gardeners often mix organic fertilizers with other more dangerous fertilizers or chemicals (e.g., organophosphates or carbamates found in some older types of rose fertilizers; spring bulbs; etc.), resulting in dual poisoning with another product.

When meals are ingested, they can result in gastrointestinal irritation (e.g., vomiting, diarrhea, etc.), foreign body obstruction (from all the bone meal congealing into a large bowling-ball-like concretion), or even severe pancreatitis (i.e., inflammation of the pancreas). Treatment includes:

  • A thorough examination at your veterinarian’s office
  • Inducing vomiting
  • Xrays (to see if the material has passed out of the stomach or not)
  • Fluid therapy
  • Anti-vomiting medication
  • A bland diet.

Rarely, with massive ingestions, “pumping the stomach” (i.e., gastric lavage) may be necessary to get the product out of the stomach. Thankfully, most dogs do well with prompt treatment and supportive care.

If you’re about to mulch your yard, pay heed! Most types of mulch are benign, but can result in a foreign body if your dog ingests them. Mulch is typically shredded tree bark, but can also come in different forms (e.g., compost or decaying matter; cocoa mulch; etc.). Cocoa mulch (which is made up from shells or hulls from the cocoa bean) is often used for home landscaping; it’s very fragrant when first placed in the yard, and smells faintly of chocolate. As a result, dogs may be tempted to ingest it. While many Internet sites discuss the dangers of cocoa mulch, it’s relatively rare for dogs to be poisoned by it. That said, there is still a small amount of theobromine (the chemical that results in chocolate poisoning) remaining in the mulch and when ingested in large amounts, this can cause signs of chocolate poisoning.

Signs of cocoa mulch poisoning include:

  • Not eating
  • Drooling/hypersalivating
  • Vomiting
  • Diarrhea
  • Anxiety
  • Hyperactivity
  • A racing heart rate
  • Constant panting
  • Dark red gums
  • Tremors
  • Seizures

The severity of clinical signs from chocolate poisoning will depend on how much cocoa mulch is ingested; in general, one or two licks or bites will not cause a problem. Regardless, make sure to keep the mulch out of reach of your dog for the first few weeks. Between sun, heat, and rain exposure, the likelihood of poisoning diminishes with time as the smell of chocolate rapidly dissipates.

What if my dog was poisoned by mulch or fertilizer?
If you suspect that your dog may have been exposed to something poisonous, contact your veterinarian or emergency veterinarian immediately. When in doubt, call ASPCA Animal Poison Control Center at (888) 426-4435. They may be able to instruct you on how to induce vomiting and whether or not there is a poisoning risk.

Most importantly, keep your dog safe this summer by keeping these garden and yard poisons out of reach! Lock your garage, keep your dog on a leash or supervised when outside, and make sure to store lawn and garden products in secure containers!

More Urban Legends

If you have any questions or concerns, you should always visit or call your veterinarian -- they are your best resource to ensure the health and well-being of your pets.


Fertilizer products generally contain varying amounts of nitrogen (N), phosphorus (P) and potassium (K) compounds. Fertilizers may be in a liquid, granular or solid form. They may have additives such as herbicides, insecticides, fungicides, iron, copper and zinc. Because fertilizers are usually a combination of ingredients, the effects following ingestion may differ. In general, fertilizers cause mild to moderate gastrointestinal irritation which may involve signs such as vomiting, diarrhoea, hypersalivation, lethargy and abdominal pain. In most cases the effects are self-limiting and resolve within 24-48 hours with supportive veterinary care. RSPCA Australia recommends that owners take active steps to ensure that their dogs and other pets do not ingest any type of fertilizer material. If an owner suspects their dog or other pet has ingested fertilizer they should contact their local vet immediately for further advice. For information relating to specific fertilizer products or any other questions regarding fertilizer ingestion by dogs or other pets we suggest you contact your local vet.

Some types of fertilizer such as bone meal and blood meal may be eaten in large quantities by dogs which can cause significant gastrointestinal upset (vomiting, diarrhea, constipation) and possibly pancreatitis. Certain fertilizers may also contain bacterial or fungal toxins which can have serious side effects if ingested.

Fertilizers can also be caustic, which irritates the lining of the gastrointestinal tract. In some cases ingestion may lead to gastrointestinal ulceration. Impaction (gastrointestinal blockage) with fertilizer material may also occur in some cases.

Symptoms may be more severe however, if a large amount of fertilizer is ingested or if additives such as insecticides and iron are part of the fertilizer mix. Some fertilizers contain a significant amount of iron which can result in iron toxicity. Though heavy metals such as iron are generally not readily absorbed into the animal’s system, they can pose a hazard when dogs ingest large amounts. A few fertilizers also contain insecticides such as disulfoton, a highly toxic organophosphate which when ingested can cause a sudden onset of seizures and pancreatitis.

Also see Animal Emergency Centre (AEC) Pet Dangers webpage for more information.


While Roundup® and similar herbicides aren’t as dangerous as disulfoton and snail bait to your pets, they can still make your pet sick. Herbicides cause vomiting, diarrhea, and deadly symptoms for senior animals. Pets with compromised immune systems are also at risk. Keep your pets – and all of their toys, bowls, etc. – inside while applying herbicides. Please wait until the grass is dry to let them outside. Once the treated area is dry, the chemical has reached the plant’s root, and the lawn can be considered animal-safe.

A chemical known as 2,4-dichlorophenoxyacetic acid, or 2,4-D, developed by the US military and used in Agent Orange is used in some herbicides. It is a carcinogen and has been known to cause a wide range of other health problems in humans and animals. These issues include birth defects, psychological issues, and tumors. In modern times, while widely used in professional landscaping, you can find 2,4-D in these herbicides:

  • Bayer Advanced All-in-One Lawn Weed and Crabgrass Killer
  • Ortho Weed-B-Gon Max
  • Scotts Liquid Turf Builder
  • Sta-Green Phosphorus-Free Weed & Feed
  • Scotts Snap Pac Weed & Feed

Make sure to read the label to know if these herbicides are safe for your pet.

Mulch And Pet Safety: Tips On How To Keep Mulch Safe For Pets

While mulch serves a variety of functions in the home garden, mulch application issues, such as toxicity to dogs, need to be addressed for the safety of your precious pets before they occur. Generally, mulch poses little threat to cats, though it can become a haven for use as a litter box. Dogs, on the other hand, often chew on some types of mulch, which can be dangerous. Keep reading more about mulch and pet safety so you can avoid any problems later down the road.


The first step in creating a garden is selecting what to grow. There are lots of plants out there that will add color and vibrancy to your garden, but some might be harmful to your dog.

The ASPCA offers an extensive list of plants both toxic and non-toxic for pets . However, here is a short list of plants poisonous to your dog:

  • Carnations
  • Daffodil
  • Apple
  • Mint
  • Lilies
  • Begonia
  • Daisies
  • Chives
  • Spring parsley*
  • Gardenia
  • Lavender
  • Leek
  • Peony
  • Tulip
  • Oregano
  • Rhubarb
  • Tomato

These are plants to avoid, as they can cause vomiting, kidney failure, tremors, diarrhea, low blood pressure, and more in your dog.

There are also lots of plants safe, and even healthy, for your dog to eat :

  • Raw green beans
  • Berries
  • Rosemary
  • Basil
  • Curly-leafed parsley*
  • Barley grasses
  • Thyme

These plants contain antioxidants, vitamins, and other chemicals that are very good for your dog, and are safe for them to consume straight from the plant or cooked into their favorite bowl of kibble.

Other, more general plants to avoid are those that are spiny and thorny, as these can not only be dangerous for your dog if ingested but can cause injuries.

*Spring parsley is toxic to dogs curly-leafed parsley is used in dog products and is safe for dog consumption.

Garden Extras

While flowers, herbs, vegetables, and other plants are essential for any garden, there are other ingredients in any garden that make it a recipe for success. These include fertilizer, pesticides, and mulch.


Pesticides to avoid: Any pesticides that include organophosphates are deadly, and can attack the central nervous system of your dog.

Snail and slug baits that contain metaldehyde will kill dogs that eat it.

Pesticides mixed with fertilizers can also be dangerous: these pesticides can contain fish and bone meal, which smell appetizing to your dog but will result in unpleasant consequences.

Pesticides to use: Essential oils are safe to use around dogs, but also have pest-controlling properties. Lavender can ward off ants lemon eucalyptus and pine mosquitos and tea tree Australia can kill fleas, ticks, and other parasites.

Boric acid is also safe around dogs, while also destroying weeds, pests, mold, and fungi.

Food-grade diatomaceous earth (DE) is also a safe and effective way to eliminate pests in your garden, while also keeping your dog safe. DE helps to get rid of all types of pests, including beetles, flies, ants, and slugs. In fact, DE can also be used to control pests on your dog! Diatomaceous earth is a powder that will need to be replaced after each rainfall, but it’s plentiful uses make it a safe and effective tool for gardening.


Fertilizers to avoid: Fertilizers that use fish emulsion, bone meal, or blood meal won’t be dangerous for your dog, but they may be dangerous for your garden. Fish emulsion fertilizers are literally made of fish, meaning it may smell appealing to your dog and they might dig up your perfectly placed garden plants.

More seriously, any fertilizers that contain carbamates and organophosphates are especially dangerous for your dog. Luckily, the EPA has cracked down on the usage of these ingredients in fertilizers. Still, to be safe, read the labels of any fertilizers for these two ingredients.

Organic fertilizers may seem safe because of the label “organic.” However, these products often contain bone, blood, feather, and fish meal, which smell appetizing to dogs and can result in ingestion. This can cause vomiting, diarrhea, and other problems in your dog.

Fertilizers to use: Fertilizers using seaweed are great for your garden and safe for your dog. Same with grass clippings, compost, and manure.


Mulch to avoid: Cocoa shell mulch should be avoided. Cocoa mulch contains theobromine, the chemical found in chocolate that is toxic to dogs. It also smells like chocolate, making it an appetizing snack for your dog out in the yard. It is rare for dogs to get severely sick from eating cocoa shell mulch, but it is still a possibility.

Using rocks as an alternative for mulch is also not recommended. Dogs may like to chew or eat rocks, which can cause them to choke or can cause more serious obstructions. Rock mulches may also hurt your dog’s feet.

Mulch to use: Mulch made of cedar, pine, and hemlock are safe for your dogs and for your garden. Although there are some concerns when it comes to certain chemicals within the mulch, rubber mulch is also safe for dogs.

Alternatives to mulch that work the same include leaves and pine needles, which are safe for dogs and also safe for your wallet.

Other things to be worried about when it comes to mulches is, if your dog eats mulch, it could lead to obstruction in their digestive system and even puncture. This can cause long-term pain and sickness in your dog. Dogs can also be allergic to certain kinds of mulch. If you fear your dog may have eaten mulch, or is allergic to mulch, contact your veterinarian.

Building a Dog-Friendly Garden

Other ways to improve your garden and improve the life of your dog are:

Giving your dog plenty of green space to safely explore, while also letting them run around and do their business.

Raising your garden beds. This will keep your dog out of the planters, but will also allow you to plant a greater variety of flowers or plants that may not be safe for your dog.

Create borders around areas you don’t want your dog to get into. These could include raised edges around your garden or planting area, as a warning against entry to your dog. Or they could be more serious, fence-like structures. Either way, these could discourage your dog from venturing into areas that may be dangerous.

Have an area for your dog to lay down and relax. This could be a tree or shrub that provides shade, a shallow pool for dipping their tongues or feet into, or just a place for them to sit and observe the goings-on in their neighborhood.

What’s your favorite thing to plant in your garden?

About Paige Johnson

Hey, there! My name is Paige and I'm a social media and content intern with dogIDs for the summer. During the school year, I study at North Dakota State in Fargo. My favorite things to do include reading, watching Netflix and cuddling with my dog, Brandy, a 10-year-old cockapoo (cocker spaniel/poodle mix).

Watch the video: Doggy Dangers: 13 Potential Garden Hazards for Dogs - Gardening Safety Tips For Pet Owners (May 2021).