THE LIST
Any with a dash have a warning, pointed out helpfully by a member (AndreaJane), so be careful on what you feed your guinea pigs!
(In order of given):
Green Bean
Dandelion - Has diuretic, so do not feed as daily food.
Cucumber
Carrot - High in sugars, again, only use for treats.
Celery
Cabbage
Brocoli
Pepper
lettuce - no Iceberg lettuce, as that can give diarrhoeal and stomach problems
Banana
Corn on the cob
Melon
Curly Kale
Apple - Acidic
Spring greens
Cauliflower
Basil
Blueberries - do not feed often, fruits are sugary and acidic.