This depends on the type of herbs you're growing and your climatic zone. Herbs such as rosemary, oregano, thyme and chives are regarded as perennials herbs and can be grown all year round in many climatic zones. However, herbs such as dill, parsley, and basil are regarded as annual herbs because they complete their entire life cycle, from seed to seed setting in one season. It's a good idea to replant these on an annual basis even when they're grown as container plants.