Question
Is it possible to grow alpines, tomatoes and cucumbers in the same greenhouse?
If not,why?

Answer
Hi Christopher,
Thanx for your question.  I'm not sure what you mean about alpines.  Tomatoes and cucumbers are hothouse grown so growing these plants in a greenhouse is an accepted practice.  I have grown tropical, deciduous, annual and perennial seedlings in the same indoor atmosphere.  Again, I ask, what do you mean about alpines?  I hope this helps.
Tom