Indoor gardening offers many opportunities for experimenting with different gardening conditions. Soil type, temperature, humidity and light can all affect plant growth.
Light can be separated into red, blue, yellow, green, violet and white spectra. Varying the color wavelength of light can have a significant influence on how plants grow. The National Aviation Space Administration studies on red and blue light effects on plant growth using LEDs sparked increased interest in manipulation of the color spectra to influence growth.
African violets are popular with indoor gardeners. These flowering plants need bright light but not direct sunlight. Fluorescent lighting (which is high in the blue wavelength) that is hung 12 to 15 inches above plants is recommended for African violets. Incandescent light, which is high in red or orange wavelengths, is also suggested for these plants. African violet foliage grows well under blue light, but unless light in the red spectrum is also present, the plants may never flower, according to Gardeners.com.
Bean plants are also good for light color experiments because they are hardy and sprout from seed easily. Plant the seeds in soil in shallow trays or in individual cups filled ¾-full with potting soil.
Red, blue, yellow and green cellophane can be used to create different colored light. Cover the tops of the bean plant containers with a different film color and mark the container with the color. Place the containers in an area that gets plenty of sunlight and measure the plants as they grow.
Keep the soil moist by watering daily. You will notice that plants under the red and blue lights grow best. On the other hand, green light inhibits growth because the bean plants absorb very little green light, reflecting it in their foliage color, instead.
You can also use soybeans for color spectrum plant growth experiments. According to Ohio State University, you can place potting soil in a 10-gallon aquarium tank, plant the beans and use red, yellow, blue, white and green film to produce different colors of light to shine on the plants. Measuring the plants' progress under different light colors demonstrates their affinity for certain color wavelengths.
According to Space.com, NASA scientists began to study light spectra and plant growth to help provide nutrition for astronauts while in space. Their experiments growing lettuce under colored LED lights demonstrated that plants require red and blue light to grow and can grow quite well without the green spectrum, although their appearance suffers. Plants reflect the green color and appear as they normally do.