7 Foods You Can Regrow from Scraps: Green Onions *frugalliving.about.com Grn. Onion, Celery, Pineapple, White & Sweet Potatoes, Garlic cloves. Green onion works well and deter some garden pests, Now trying organic Celery. Good to keep planting so youll have a continuous staggered harvest. IMO It's just fun to eat what you grow.