I generally buy organic groceries at my regular grocer (Loblaws/ Real Canadian Superstore), and most other stores have organics sections as well.
EWG's Shopper's Guide to Pesticides in Produce
Dirty Dozen (Buy these organic)
1 Apples
2 Celery
3 Strawberries
4 Peaches
5 Spinach
6 Nectarines – imported
7 Grapes – imported
8 Sweet bell peppers
9 Potatoes
10 Blueberries – domestic
11 Lettuce
12 Kale/collard greens
Clean 15 (Lowest in Pesticide)
1 Onions
2 Sweet Corn
3 Pineapples
4 Avocado
5 Asparagus
6 Sweet peas
7 Mangoes
8 Eggplant
9 Cantaloupe - domestic
10 Kiwi
11 Cabbage
12 Watermelon
13 Sweet potatoes
14 Grapefruit
15 Mushrooms