Hello Lucie, and welcome to the forum.
I try to buy the dirty dozen in organic form. I actually prefer organic, but don't always buy it, unless it's on sale. As it turns out, sometimes the organic will be on sale for less than the non-organic. If it's only 20 cents per pound difference, I buy organic. There's other fruits and veggies that are not on the dirty dozen that I always buy organic as well...like bananas, for example. The price between non-organic and organic bananas is negligible.
The dirty dozen will vary from website to website, but you can see from this one below how it works. Some things are naturally resistant to pests, like onions. I never bother even looking for organic onions, asparagus, avocados, etc. I try to watch my budget, but I will keep as much organic as I can, when possible.
The fruits and vegetables on “The Dirty Dozen” list, when conventionally grown, tested positive for at least 47 different chemicals, with some testing positive for as many as 67. For produce on the “dirty” list, you should definitely go organic — unless you relish the idea of consuming a chemical cocktail. “The Dirty Dozen” list includes:
- celery
- peaches
- strawberries
- apples
- domestic blueberries
- nectarines
- sweet bell peppers
- spinach, kale and collard greens
- cherries
- potatoes
- imported grapes
- lettuce
All the produce on “The Clean 15” bore little to no traces of pesticides, and is safe to consume in non-organic form. This list includes:
- onions
- avocados
- sweet corn
- pineapples
- mango
- sweet peas
- asparagus
- kiwi fruit
- cabbage
- eggplant
- cantaloupe
- watermelon
- grapefruit
- sweet potatoes
- sweet onions
Source