I live in Idaho Falls, Idaho and I built a garden space bordered with 3.5″ x 5.5″ treated lumber. I wanted to line each side with cedar fencing about 14″ tall to form planters for strawberries. The interior dimensions of the planters would then be roughly 3.5″ wide x 8.5″ high. Will this be suitable for a successful strawberry harvest?
You can successfully plant and grow strawberries in containers. Hanging baskets or a planter such as the one you have built.
Don't forget to put drainage holes in your planters.
Here is a couple links with more information.