... light, then they should grow faster and better.

Set up: There are four plants: Green Bean, butter bean, rye grass and a sunflower. These plants grow rather quickly. The green bean plant is placed under white light and is used as the control. The butter bean is placed under green light, the rye grass plant under red light and the sunflower under blue light. All the plants are watered one cup of water every other day and kept under the light the same amount of time. At the end of 4 weeks, the sunflower plant grows the most.

What is wrong with this experiment?