It was said that cucumbers, like lentils and onions, represent something disliked, because of the Verse:
“So invoke your Lord for us to bring forth for us of what the earth grows,its herbs, its cucumbers, its Fum(wheat or garlic),its lentils and its onions.
And it was said that they are indicative of pregnancy of thedreamer’s wife. And it seems that if they are seen before their season, they are indicative of trouble.