Question

a hypothesis for can a plant grow with a regular light bulb

Answer 1

Welcome to OS ;)

Answer 2

First, what are the manipulated and responding variables? Next, can you relate them?

Answer 3

You need another variable to experiment with. If you are testing whether plants grow faster under different types of light bulbs, let's say 7-watt and 14-watt lights, then you can say "If a plant is grown under a 14-watt light, then it will grow faster." For that experiment you would also need a control group, which you could have plants growing near a window or in your backyard (some place they have sunlight so they're in their natural growing environment or something similar).