Dig and pour your deck footings so they extend below the frost line. That way, they won't move, or heave, as the ground freezes and thaws during seasonal changes. This article explains how to build solid footings that will stay put year-round.
No-Dig Deck Footings Some pros have given up constructing concrete deck footings. Instead, they're using the Diamond Pier foundation system. To install a Diamond Pier footing, just drive in four pipes with a demo hammer. That eliminates a ton of digging and concrete work.