For indoor plant growers, getting enough usable light for plants can be a bit tricky. For one, the cost of indoor lighting for plants can quickly escalate to levels that really dent a pocketbook. Fortunately, plants only actually need two of the seven colors of light contained within visible light. Therefore, it can be relatively inexpensive to create cheap grow lights that give plants the colored light they need. For example, fluorescent lighting contains plenty of blue light, which plants love.
Fluorescent lights are also known as cool white lights, and they contain plenty of the blue light that plants thrive on. What's really attractive about using fluorescent lighting for growing plants is that it's fairly inexpensive. Additionally, because plants need blue light to power their leafy growth, fluorescent lighting of any type can figuratively supercharge growth. Standard T12 fluorescent light tubes, for example, paired in a common overhead fixture can grow plants quite well.
Incandescent light is high in red-colored light, which is needed by a plant to regulate its flowering and reproduction, and it's also extremely inexpensive. Setting up incandescent lighting around a plant is as easy as pointing a lamp and light bulb at it. However, be aware that incandescent bulbs create a great deal of heat, so positioning them far enough away from a plant is paramount. If plants are exposed to excess heat from any source, they'll eventually die.
Indoor plant growers often position hanging shop light-type fluorescent fixtures over their plants; in 2011, a two-tube fixture only costs about $30 and fluorescent tubes run about $4 apiece. One fluorescent shop light fixture that's 2 to 4 feet in length can provide enough light for the same length in plant rows. Incandescent grow lights are also inexpensive, costing about $4, and can be positioned over lamps from common existing light fixtures and lamps.
Fluorescent lighting is much cooler to the touch than incandescent lighting when it comes to cheap plant grow lights. However, to be effective, fluorescent lighting should only be about 1 to 10 inches away from a plant. Incandescent lighting for plants is brighter, but it's more inefficient than fluorescent lighting at growing plants. If you position fluorescent lights over your plants, consider occasionally providing red light by adding incandescent lighting.
Though plants only need blue light and red light in order to grow, they grow much better exclusively under blue light than they do red light. Plants exposed only to red light will grow tall, but their growth will also be thin and spindly. Blue light gives plants all they need in order to grow many broad leaves and lots of branches. If budget is most important when it comes to selecting a specific color of plant grow light, choose blue.