You are getting ready to set up a “do-it-yourself” greenhouse, so you can grow the biggest, juiciest vegetables, even during the winter. to do this, you want to know the conditions that are best for plant growth/photosynthesis. you know that plants need water, something from the air, and light to grow, but what kind of light is best? plant lights aren’t white, so they must be better than sunlight or they would be white – wouldn’t they? how much light do they need? what do they need from the air, and how much?