If Not, please suggests water-solutions that would be helpful. Eg. Water + Sugar etc. This is an experiment i'm doing for school, so i dont have much time.
The Harebell (if that's what you're talking about) needs soil to grow, but what it requires most is light. Indeed, this plant is not a house plant at all. Either you have a grow light (made of two bulbs: one with a 6500K spectrum and another with 3000K spectrum to induce flowering) at home, or you will have to take it outside and grow in a pot (which I will do in about a month).
All you can do is grow the plant outside and collect the flowers when they are blooming to bring them indoor. Normal tap water is most of the times just enough for this task, and it will be enough to complete the blooming of the whole stalk you cut.