Miracle-Gro is a gardening aid intended for use as a plant food supplement. While the product is not poisonous to dogs in small quantities, it can cause irritation to the dog's digestive system.
The Food and Drug Administration classifies Miracle-Gro as GRAS, or Generally Recognized as Safe. According to Scotts, the company that manufactures Miracle-Gro, pets are allowed in an area treated by the product after the Miracle-Gro dries and washes into the soil. If a dog ingests a small amount of Miracle-Gro, the dog may vomit and develop diarrhea. Ingestion of large amounts of the product can cause the dog to exhibit signs of weakness and decreased body temperature. In either case, it is recommended to contact the dog's veterinarian as soon as possible.