A good mulch is a gardener’s best friend, but when it puts another best friend’s life in jeopardy, it’s not worth the risk. If your dogs are anything like mine, they’ll put almost anything in their mouths, including mulch.
While a mulch made of untreated wood isn’t likely to cause harm even if your dog ingests it, others can cause vomiting and seizures.
Is Mulch Bad for Dogs?
Yes, mulch can most certainly be bad for dogs. However, it depends on which mulch you choose. The most dangerous mulch for dogs is cocoa bean mulch. This mulch must be avoided around dogs, especially if your dog likes to chew on everything! Cocoa bean mulch contains caffeine and theobromine, neither of which your dog can metabolize.
Ingesting as little as 20 mg/kg can show mild signs (bloating, vomiting, diarrhea) of chocolate toxicosis, with more severe issues (muscle tremors, hyperthermia, seizures) occurring at 40 mg/kg and up. Higher levels are potentially fatal to your dog.
Outdoor Happens is reader-supported. When you buy through links on our site, we may earn an affiliate commission. Click to learn more
The safest mulches for your dog are organic seeding mulch, natural cedar shavings, shredder rubber mulch, untreated wood mulch, and cypress mulch.
Note that even these mulches can cause issues to your dog’s digestive system, especially if they contain chemicals or the particles are big enough to block their digestive system.
Read on for more details on how dangerous cocoa bean mulch is for your dog, and the best mulches for a dog-safe garden!
How Dangerous Is Cocoa Bean Mulch for Your Dog?
The most dangerous type of mulch is one made of cocoa bean shells. It smells delicious even to humans, and dogs find it almost irresistible. A fussy cat may even sample a bean or two but will rarely consume enough to cause a problem.
Cocoa bean mulch is advantageous for the garden, with its beneficial nutrients and attractive appearance. It contains nitrogen, phosphate, and potash, all of which increase growth, strengthen roots, and boost your plant’s water uptake.
Unfortunately, it also contains toxic compounds known as methylxanthines, specifically theobromine and caffeine.
Dogs can’t metabolize either of these compounds the same way humans can, and even a limited amount can cause vomiting and muscle tremors.
According to one dog owner, cocoa bean mulch can even be fatal. Almost every year, a story circulates about a dog named Calypso who allegedly ate enough cocoa bean mulch that she later collapsed and died.
Dr. Maureen McMichael, a veterinarian at the University of Illinois Veterinary Teaching Hospital, warns that “Cocoa mulch is significantly more toxic than milk chocolate or even baker’s chocolate because it has quite a bit more theobromine in it.”
Furthermore, “many of the dogs that present with a history of eating cocoa mulch do not survive if… not stopped quickly.”
On the other hand, Dr. Steve Hansen, the director of the American Society for the Prevention of Cruelty to Animals Animal Poison Control Center, believes that ingesting cocoa bean mulch is unlikely to kill a dog.
Every year, the organization receives numerous reports of dogs who are vomiting or trembling after eating cocoa bean mulch, but none about pets experiencing lethal toxicosis as a result.
Hansen and his colleagues conducted a study into the effects of cocoa bean mulch on dogs.
Their findings revealed that “Dogs that consume cocoa bean shell mulch might develop signs consistent with methylxanthine toxicosis…. These signs are similar to those seen in chocolate poisonings”.
Despite that, Hansen maintains that few dogs find cocoa bean mulch appetizing enough to eat a fatal quantity.
A dog that ingests 20 mg/kg of theobromine and caffeine will show mild signs of chocolate toxicosis, with more severe symptoms starting at 40-50 mg/kg and seizures occurring if it eats more than 60 mg/kg.
This means smaller dog breeds and puppies are more at risk than larger adult dogs, as they only need to consume a small amount of mulch to experience its severe and potentially fatal effects.
How to Identify Cocoa Bean Mulch Poisoning In Dogs
If you’ve used cocoa bean mulch in your garden, watch out for vomiting and diarrhea in your dog. These are the most common signs observed within the first six to 12 hours of ingestion.
As more time passes, so the symptoms increase in severity. If your dog shows any of the symptoms below, you should call the Pet Poison Helpline on 800-213-6680 and get him to a veterinarian as quickly as possible:
- Excessive thirst
- Restlessness and hyperactivity
- Muscle tremors
- Increased heart rate
- Rapid breathing
The Potential Dangers of Different Types of Mulch to Dogs
Although cocoa bean mulch is by far the most dangerous, it’s not the only one that could negatively impact your dog’s health.
Some types of wood chip mulch contain potentially dangerous resins and oils, although they aren’t are temptingly fragrant as cocoa bean mulch. Others contain pesticides, and that may affect the dog’s nervous system.
Even some pet-friendly mulches can cause problems for dogs that eat everything.
Rock-based mulches are some of the safest but can cause nasty digestive complications if ingested. They can also cause choking, as can some types of rubber mulch.
Coir or coconut husk mulch is widely considered dog-friendly, even though its ability to retain water means it could expand in your dog’s digestive tract, causing a dangerous blockage in the intestines.
Similarly, the needles contained in pine needle mulch “can puncture or irritate the lining of your dog’s stomach, and the oils can irritate the mucous membranes.” (Source.)
Top 5 Best Mulches for Dogs
#1 Organic Seeding Mulch
Made of organically grown straw, this type of mulch is both dog and child-friendly.
It doesn’t contain any dyes or pesticides and is small enough to pass through a puppy’s digestive system.
This processed hay mulch is perfect for garden beds and helping grow grass. It protects from birds eating your seeds - and the straw biodegrades. We also love it as a barrier to keep your dogs (and their paws) out of the mud!
#2 Natural Cedar Shavings
This mulch has a pleasant fragrance, but it won’t tantalize your dog’s tastebuds the way cocoa bean mulch does.
Not only is it safe for your dog, but it also repels insects while adding nutrients to the soil.
Cedar shavings are perfect for gardening, crafting, and many other artisan crafts. Can also be used as animal bedding due to its absorbency and odor-fighting abilities. 100% natural.
#3 Shredded Rubber Mulch
Rubber mulches are made from recycled tires, so are eco-friendly as well as non-toxic (check the packaging to make sure they are non-toxic).
Some contain larger rubber nuggets that could cause choking so, look out for a shredded rubber version instead.
#4 Untreated Wood Mulch
While this is a potential choking hazard, if you select a finer mulch of wood shavings, you can combat this problem.
These are 100% red oak. No chemicals or additives come into contact with these shavings
#5 Cypress Mulch
Cypress mulch is widely available and commonly used. It’s not toxic to dogs but can cause an intentional obstruction if your dog makes a meal of it.
Final Thoughts on the Safety of Mulch for Dogs
Cocoa bean mulch smells so delicious that few dogs can resist it. Although they’re unlikely to eat enough to have fatal consequences, the chemicals it contains can easily cause vomiting, diarrhea, and muscle tremors.
Few types of mulch are as dangerous to your dog as cocoa bean mulch, but many can adversely affect his health.
Even dog-friendly mulches made of rubber or wood chips can cause issues with a dog’s digestive system, while others contain pesticides and other chemicals that are toxic to pets.
The more natural the product, the safer it is to use, so I think we’ll stick with the grass our horses leave behind and avoid the commercial products altogether.
If that isn’t an option for you, opt for a mulch made of straw or untreated wood with particles small enough for your dog to digest.