Place peppers and water to cover in a small saucepan; cover and bring to a boil. Cook 5 minutes; drain and cool. Remove seeds from peppers, and finely chop peppers.
Combine chopped peppers, tomatoes, onion, and garlic; mix well. Cover and refrigerate overnight to blend flavors. Stir sauce well before serving.
Note: Vegetable Hot Sauce can be refrigerated up to 2 weeks.