Mercury Lighting systems are ideal for use in a greenhouse as they produce a type of light that is good for plant growth. Mercury lights are also energy efficient and long lasting - mercury lights waste very little energy in heat (compared to other lighting systems) and use up to 75% less energy than an ordinary light bulb yet last 10 times longer.
A Mercury light bulb produces light by running electricity through argon gas and a small amount of mercury vapour. The mercury bulb (or lamp) produces an intense bluish light, resulting in a relatively well-balanced, high intensity light. Sunlight contains the full spectrum of light - red through yellow to blue and violet. Plants use the full spectrum of light for photosynthesis, although red and blue light is the most important. Red light stimulates vegetative growth and flowering but if a plant gets too much red light it will become tall and spindly. Blue light regulates plant growth, making it ideal for growing foliage plants and short, stocky seedlings.
A mercury lighting system that includes a polished reflector will ensure uniform illumination, whilst the intensity of light that a plant receives is determined by the wattage of the light bulb and how close the plant is to the light. Plants differ in their needs for light intensity - generally plants native to tropical jungles or shady forests do not require as much light as those plants native to dry, sunny climates.