Plants require adequate lighting for healthy growth. However, not all light is equal. Plants need a blend of colors, specifically blue and red, to initiate photosynthesis, the process by which a plant generates food. When sunlight is not available, gardeners turn to artificial lighting. Choosing an artificial lighting source depends on the scope of your project. Serious horticulturists may invest in more effective lighting sources that cost more but use less energy. However, gardeners looking to supplement houseplants or start seeds indoors may opt instead for traditional solutions to lighting concerns.
Fluorescent and Incandescent
Gardeners may use fluorescent lighting indoors to supplement sunlight. According to Colorado State University (CSU), fluorescent lighting can accommodate for approximately 70 percent of supplemental lighting. However, CSU also recommend using an incandescent bulb to provide the best indoor lighting conditions. Fluorescent lights have a higher light efficiency than incandescent lights, but incandescent lights put out more red light, which convert into heat. This is an effective combination for houseplants and seedlings. Use two 40-watt cool white fluorescent tubes in combination with one incandescent.
Full Spectrum Fluorescent
Full spectrum fluorescent bulbs are made to mimic the natural solar spectrum. This means a specific unit of each of the full spectrum colors found in natural lighting. According to Garden's Supply Company, you can use these lights on flowering plants as well as other houseplants to provide approximately 98 percent of the lighting that a plant would receive from the sun. In addition, you can use these bulbs in any fluorescent bulb fixture.
High Intensity Discharge
High intensity discharge (HID) lights are artificial lighting used by commercial growers. These lights emit twice the amount of blue and red light as incandescent and fluorescent yet use approximately the same amount of energy. However, fixtures and bulbs for this type of lighting tend to be more expensive, so HID lights are best suited for large horticultural projects where savings from energy costs will balance the high equipment expense. HID lights include metal halide, high-pressure sodium and mercury vapor lights, all of which will help produce plants that have healthy green foliage but remain compact and stocky.