The Single-most Critical Strategy for Growing Fresh Veggies Through the Cold of Winter
(Check your email for bonus video on 5 gardening keys)
Calculate Your Agriculture Zone
(National Gardening Association)
Calculate Your Average First and Last Frost Dates
(Dave's Garden)
Fall Planting Calculator - Johnny's Selected Seeds
(simple but effective)
Fall Planting Calculator - Seeds for Generations
(requires opt-in but is a bit more detailed)