Zone 4A is a cold-winter zone where season extension techniques pay dividends. With an average last spring frost around May 8 and first fall frost around Sep 25, you have approximately 140 frost-free days per year. Use the planting dates below to plan your garden around these key frost windows. For a personalized forecast based on your specific zip code, use our free planting calendar. Browse individual plant guides for detailed growing instructions, or explore how USDA zones work to better understand your growing conditions.