Soak oats in 1 cup (237 ml) warm water for 30 minutes to soften. Drain well.
Grate apples, then toss with lemon juice in a medium-sized bowl to help prevent discoloration. Add soaked oats, berries, grapes, and nuts.
Stir honey and yogurt together and add to oats, tossing lightly. Refrigerate several hours or overnight.
Serve with fruit and additional yogurt or cream.