Guinea pigs must have at least one cup of fresh vegetables each day each. Good veggies to offer daily include:
Lettuces - all types but iceberg (contains mostly water and very little nutritional value), Good lettuces are Romaine, Green/Red leaf, butterhead/boston, curly or belgian endive, raddichio and others.
Cilantro (coriander)
Peppers - all colours, no seeds
Baby carrots - one small/medium per pig or same equivalent of regular carrot.
Chard, Red or Swiss is most commonly preferred
Zucchini (Courgette)
Corn husks and silks
Cherry/grape tomatoes (no more than 1-2 per pig)
Good every other day foods:
Parsley
Celery - chopped up small plus leaves
Cucumber
Broccoli leaves
Dandelion greens
Green beans
Summer and Winter squash (all varieties)
Chicory Greens
Some fresh foods should be limited to twice per week:
Fruits - apple, plum, apricot, melon, cucumber, peach, grapes and a few others.
Cabbage
Broccoli
Herbs such as Dill, Chives, Basil, Mint, Thyme
Collard Greens/Turnip Greens/Mustard Greens
Kale
Spinach (in small amounts)
Asparagus
Beets
Brussel Sprouts
Cauliflower
Sweetcorn on the cob
Pumpkin
Turnips
Other foods, such as radishes, banana, sweet potato and beet greens should only be given as occasional treats, say once or twice a month.
Vegetables are important to provide essential vitamins, and if provided with a good variety of fresh foods daily, there is rarely a reason for supplements of any kind to be given.