These are the main source of nutrition for cavies. You can buy special guinea pig pellets or you can get mixes which contain pellets, maize, grass and added vitamins and minerals. Guinea pigs cannot produce their own vitamin C so you must provide a dry feed with adequate vitamin C content. The dry food must be avilable at all times to prevent over grown teeth.
There are a variety of vegetables suitable for cavies.The following are some examples.
Spinach - in small amounts due to oxalic acid content.
Lettuce - in small amounts due to low nutritional value.
Hay and grass - should be readily available.
Anything grown from bulbs