You are in Medical Library . The ultimate outcome depends on how much was ingested, how soon it was diluted, and how soon proper medical care was administered.
Fertilizers are unlikely to cause serious harm unless burns or an allergic reaction occur.
They will instruct you if it is necessary to take the patient to the hospital. See Poison Control centers for telephone numbers and addresses. Take the container with you to the emergency room. Dilute with fluids. Treat the symptoms.