Not all light is equal. There are wavelengths in the spectrum that the plant doesn’t use in the process of photosynthesis, for example. But light sources also provide another output: heat. T5 fluorescents produce more ambient heat than LEDs which at times could be advantageous in the Lab and detrimental under different circumstances. Energy consumption is yet another concern.

But for the most part, the value of lighting in a production scenario lies in the unit’s ability to promote plant growth at an optimal level. So how do you know which is best when your choices might include fluorescents, LEDs, metal halide, high-pressure sodium, and others?

Create an experiment to explore how plants react to various types of light sources. Use sunlight as the control and position all other sources at a standard distance from the plants. Introduce plants to various types of grow bulbs, wattage, and colored lights. Use any light sources you can find and document the plant reactions. Observe and measure the rate of response for phototropism, the rate of growth by measuring the stems periodically, and total leaf production. Which light source proves most effective? Least effective? Can you speculate as to why? How does the quality of light affect photosynthesis, the catalyst for root, stem, and leaf production?