My Dog Ate Fertilizer, Now What?

By Veronica Higgs, DVM on Sep. 23, 2022

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Why is fertilizer toxic to dogs?

Most fertilizers contain varying amounts of nitrogen, phosphorus, and potassium, ingredients listed on the bag with numbers such as 5-10-10, meaning 5 percent nitrogen, 10 percent phosphorus, and 10 percent potassium.

In general, fertilizers have a low-level toxicity and symptoms are typically mild and limited to gastrointestinal irritation. However, when additional nutrients or additives are added to fertilizers, the potential for toxicity can increase. Here are some common additive ingredients found in fertilizers and the concerns associated with them:

Common Ingredients Added to Fertilizers	Concern for Dogs
Micronutrients including iron, sulfur, calcium, magnesium, copper, zinc, boron, manganese, and molybdenum	Typically, these will be in low concentrations in fertilizers, but the iron can be an issue if a large volume is ingested. The most common initial clinical signs of iron toxicity are vomiting, diarrhea, and anorexia.
Animal by-product meals (fish, bone, blood, and chicken feather meals)	“Organic” fertilizers will often contain animal by-products. Unfortunately, they smell and taste good to animals and may result in large ingestions. This may cause increased clinical signs such as vomiting and diarrhea, but also large amounts of bone meal can form a large, cement-like rock in the dog’s stomach that can cause an obstruction and even require surgery. Severe inflammation of the pancreas (pancreatitis) is also a possible consequence of ingestion.
Rose fertilizer (disulfoton)	Disulfoton is a highly toxic insecticide often included in rose fertilizer. About one teaspoon of 1 percent disulfoton could be lethal to a 55-pound dog. This ingredient is extremely dangerous.
Cocoa bean mulch	Cocoa bean mulch is made from the shell of the cocoa bean so dogs ingesting it can experience obstruction from the hulls themselves as well as chocolate toxicity.
Sewage-based (milorganite)	Fertilizers containing milorganite have a higher risk of toxicity with the potential for gastrointestinal signs, muscle pain, and stiffness.
Herbicides	There are over 200 active ingredients used as herbicides but most modern herbicides have a relatively low toxicity for dogs.
Pesticides and Insecticides	Some pesticides and insecticides are relatively harmless to mammals and cause only mild gastrointestinal irritation, if ingested. However, others containing ingredients such as organophosphates, carbamate, some pyrethroids, and more can be toxic to dogs and cause more severe clinical signs such as tremors or seizures.
Fungicides	Fungicides are chemicals that destroy fungus and their spores. They can range from non-toxic to toxic and identifying the specific ingredient in fertilizers is crucial to determining toxicity.
Corn Cobs	Corn, and subsequently corn cobs, are often used as filler in fertilizers. Any large pieces of debris such as mulch, hulls, rocks, or in this case corn cobs can create an obstruction in dogs resulting in the need for surgery. Due to the enticing nature of fertilizers to the dogs, it is recommended to remove any large chunks, pieces, or corn cobs seen in the fertilizer when spreading.
Anhydrous Ammonia	Anhydrous ammonia is typically found only in commercial fertilizers and often used on farms. However, it is highly corrosive, and contact can result in severe burns to skin, eyes, or mucous membranes.
Manure	While gross to think about, manure is a commonly found additive in fertilizers that is only slightly toxic to dogs. The main clinical signs are vomiting and diarrhea when ingested in large amounts.

Types of Fertilizer

Fertilizers typically come in three forms—solid, liquid, and granular. None of these fertilizers should be ingested, even if they are labeled “safe for pets.” It is best to always store your fertilizers, and other lawn and gardens products, safely away from pets in sealed containers.

If a liquid product is applied to the yard, typically it is no longer toxic once dry, so it is best to keep your pet inside until the product is completely dry. Granular or solid formulation usually has a lower risk once spread across the entire yard, even if the pet were to lick its paws after running through the yard.

The bigger risk is if the dog gets into the entire bag or spreader full of fertilizer. Always follow the manufacturer’s specific instructions on applying the fertilizer and the period of time before the yard can be accessed. As a rule of thumb, keep pets off the yard for 48 hours after applying fertilizer.

How Much Fertilizer Does it Take to Poison a Dog?

Typically, only mild toxicity results if the fertilizer has been properly diluted, or if a pet parent uses ready-to-use fertilizer according to label and manufacturer's directions. Symptoms are limited to mild gastrointestinal irritation. Toxicity from traditional fertilizers with low concentrations of nitrogen, phosphorous, and potassium is low.

The risks of fertilizer poisoning become higher when the dog gorges itself on large quantities when there is free access to a bag of fertilizer and/or if the fertilizer contains additives (see chart above). Determining what ingredients are present in the fertilizer ingested by your pet is crucial for determining toxicity.

While the biggest concern for fertilizer toxicity is your dog gaining access to an entire bag or full spreader, it is also important to think about any possible plants your pet may have ingested if it was eating fertilizer off the ground, or in flower beds. This is a list of common poisonous plants to dogs.

Additionally, fertilizers can become moldy, and the mold can cause tremorgenic toxicity, meaning you can see vomiting, lack of coordination, tremors, and even seizures. Be sure to mention any possible concurrent toxicities such as toxic plants or mold when discussing your pet’s fertilizer ingestion with your veterinarian.

Symptoms of Fertilizer Toxicity in Dogs

Clinical signs are usually mild and occur within 2 to 10 hours after ingestion. Symptoms typically resolve after 12 to 24 hours. The clinical signs of fertilizer toxicity in dogs may include:

Hypersalivation/Vomiting
Diarrhea
Abdominal pain
Anorexia
Lethargy
Less common is rash, a swollen muzzle, and itchiness

If concurrent toxicity with additives (see chart above), you may notice additional clinical signs including:

Muscle pain or stiffness
Uncontrolled urination or defecation
Irritation to the skin, eyes, or mucous membranes
Disorientation or loss of balance
Tremors or seizures

What should I do if my dog eats fertilizer?

If your dog ate fertilizer, the first thing to do is to try to determine how much and what type of product it consumed. Next, it is important to verify which specific ingredients were present in the product (such as iron or disulfoton). It is helpful to have the packaging (or what is left of it) from any product your pet ingested.

Gather as much information as possible and call your veterinarian to discuss whether your pet needs to be seen. You can also call the Pet Poison Helpline at 855-764-7661, or the ASPCA Animal Poison Control Center at 888-426-4435 for more help in determining if your pet needs to go to an emergency room.

Should I induce vomiting if my dog ate fertilizer?

Do not induce vomiting at home unless you have been specifically instructed to do so by a veterinarian. If you think your pet ate fertilizer, or you saw it eat fertilizer, the best thing to do is to call your veterinarian to determine if our dog needs to be seen.

Treatment of Fertilizer Toxicity in Dogs

If you see your pet eat fertilizer, call your veterinarian or veterinarian hospital immediately. They will collect a thorough history, including packaging and/or the detailed label ingredients. It may be easier to look the specific product up online so the vet can easily evaluate the ingredient list.

If your pet ate fertilizer within the past two hours and it was a large amount, your veterinarian may recommend inducing vomiting at the hospital as a means of decontamination. In severe cases, your pet may need to be hospitalized for IV fluids and additional therapy.

Severe cases include ingestion of fertilizer with highly toxic additives, potential for intestinal obstruction, or concurrent ingestion of toxic plants.

A complete blood count, serum blood chemistry, and urinalysis will likely be recommended for a baseline evaluation. Your veterinarian may also recommend abdominal X-rays to assess how much your pet ingested, as well as if there is an obvious obstruction.Prognosis of Fertilizer Toxicity in Dogs

Most dogs recover from eating fertilizer without any short- or long-term complications. However, depending on the fertilizer additives (or possible complications such as an obstruction or ingestion of a toxic plant) your pet may need more aggressive therapy. Fertilizer toxicity is typically considered a low risk, but care should be taken to determine the exact exposure of specific ingredients.

Prevention of Fertilizer Toxicity in Dogs

As with most toxicities, prevention is the key! Dogs are drawn to the odors in fertilizer and will often eat large amounts if they can gain access to the bag. Do not leave any lawn and garden product in easily accessible places such as on the floor of a garage, in the yard unattended, or in an unattended spreader. The best way to prevent fertilizer toxicity in dogs is to keep all lawn and garden products in a safe and secure area that is inaccessible to your canine friend.