Hard Vegetables (Potatoes, Carrots, Beets, etc.): Marinate these veggies for at least 30 minutes and up to overnight. Semi-Hard Vegetables (Green Beans, Asparagus, Peppers, etc.): Marinate for at least 30 minutes and up to several hours. Soft Vegetables (Broccoli, Tomatoes, Greens, etc.): About 10 minutes is good.