It can be very stressful for you and your dog when he swallows something potentially harmful. Dogs are notorious for rooting around in cabinets and other places to get at food, and the often sweet smell of plant foods can be very attractive to your furry friend.
Synthetic Plant Food
Synthetic plant foods, such as MiracleGro or Scott's Lawn Fertilizer, are made from chemicals synthesized in a laboratory. Because of the high chemical concentrations, even low quantities of most of them will cause vomiting, nausea and even death for a dog. Some synthetic plant foods are non-toxic in small doses.
Organic Plant Food
Organic plant foods (seaweed, compost, etc.) are generally much less toxic to dogs. They contain much lower concentrations of chemicals per volume than synthetic fertilizers.
Weed killers or other sprays you may use around plants are poisons and extremely toxic to dogs. Even in small quantities, weed killers may cause death, and will almost certainly cause vomiting, nausea, and even organ failure.
Keeping Dogs Away from Plant Food
Take the same steps to dog-proof your house as you would to child-proof it. Install locks on any kitchen cabinets within the dog's reach, put away any dangerous materials once you're done with them, and keep your dog out of the yard while fertilizing plants.
If Your Dog Eats Plant Food
If your dog begins vomiting or drinking excessive amounts of water, take him to the vet immediately. If you don't have a family vet, contact your local poison control center.