What else did you eat? Was there any dressing on your salad?
Did you carb count?
Did you take insulin for your meal?
Sorry for all the questions but whilst we may be told not to bother counting the carbs in vegetables, when we eat a large plate of salad, the amount of carbs may be significant.
Alternatively, the rise may have nothing to do with the tomatoes, peppers or anything that you ate.
For example, are you stressed? Are you going down with an illness? Are you confident of your last BG reading or could you have something on your fingers? Is it possible your insulin is not ok? Is it possible you pen did not deliver your insulin correctly?