Place the wheat berries in a medium saucepan and cover with about 2 inches of water. Add 1 teaspoon salt.
Bring to a boil, reduce heat, cover and simmer gently for about 1 hour. Stir occasionally. Drain.
To make dressing, combine olive oil, apple cider vinegar, dry mustard, 4 teaspoons honey, salt and pepper in a small bowl and whisk well to combine. Set aside.
To make walnuts, combine walnuts, 1 1/2 teaspoons honey, and red pepper in a small nonstick skillet and cook over medium heat for about 3 minutes, stirring occasionally.
Place wheat berries in a medium bowl and add in apple, celery, grapes, and blue cheese. Add dressing to taste and toss well. Sprinkle with walnuts.