It is best to eat organic all the time but especially while on the detox. You want to avoid putting chemicals and pesticides in your body or on your skin while detoxing. If you can’t find everything organic, its most important that the veggies you juice (if you are participating in level 2) are organic, and I recommend at least buying the following from the “Dirty Dozen” organic (Strawberries, Spinach, Apples, Celery, Tomatoes, Potatoes) as these fruits and vegetables have the most pesticide residues on/in them. Also imported produce from Chile and Mexico is likely to be coated in pesticides banned in the U.S. American-grown produce is preferable, although U.S. growers do use plenty of harmful chemicals.
If you must buy conventional produce for your detox, please use a good organic veggie wash, available at any health food store or online. You can also make your own inexpensively.