(Question)
Where can I buy organic Lawn Fertilizer?
(Answer)
Organic fertilizers are usually made from dead or composted plants and animals. Some examples would be blood meal, fish emulsion, and manure. For lawns you would want to apply one that is high-nitrogen such as 28-7-14 to stimulate deep green growth.
Toronto Master Gardeners give gardening advice but do not provide recommendations for specific nurseries. Your local garden center should carry organic fertilizers. If not then Landscape Ontario has an excellent search function, where you can find centres close to your home on-line.