Infrared light waves range between the light that humans can see unaided and microwaves. It is a specific light in the electromagnetic spectrum and can affect how a plant grows. The closer the infrared waves are to the microwave end of the electromagnetic spectrum, the more they are experienced as heat instead of light.
Infrared waves can increase the speed of growth for plant stems. A balance of red light and far infrared light can greatly increase the growth of internodes within the plant. Short exposure to infrared light alone will increase the growth while plain red light can reverse the effect. Plants that grow in light that is too red for too long will develop awkward stems that are both overly long and thin.
Texas A&M University has stated that infrared light is important in the blooming of flowering plants. Plants will not bloom under ordinary fluorescent light that does not contain the proper levels of infrared radiation.
Infrared light waves are sometimes used to measure the growth of plants during experiments. By injecting a unique radioactive substance into the plant, scientists are able to analyze the cellular development of plants using infrared cameras.
Infrared light from the far, red end of the electromagnetic spectrum can damage plants. The heat from radiation can burn the plant cells, especially with plants that are dehydrated. Infrared light can also cause plants to flower and grow too early, forcing the plant to use too much energy before it has the necessary resources to maintain the growth.
Indoor gardening requires a balance of infrared light to properly aid in plant growth. Conventional bulbs sometimes provide the plant with too little or too much light, resulting in unhealthy plant development. Gardeners worried about a plant's lack of life can find specialized lights for proper infrared growth at local garden stores.