Halogen lamps are not the best form of lighting for growing plants, but they will produce results. Halogens are 25 to 30 percent brighter than regular incandescent bulbs. They stay brighter longer, and have a life of 2,000 hours. The reason they are not ideal for plants is because they are a good source of light from the red end of the spectrum, but do not provide much light from the blue end of the spectrum. The light intensity is reduced. However, with supplementation of natural light or other artificial lights, plants will thrive under halogen lights.
Set the halogen lights up about 6 to 12 inches from the tips of the plants. As the plants get farther from the light, the intensity of the light diminishes. Halogen lights are not as strong as other types of light, so use a couple of lights per plant. Use a fixture you can adjust, so you can raise it as the plants get taller.
Give plants 16 to 18 hours of halogen light daily, if they are not getting any natural light. Plants near a window can grow with 12 to 14 hours daily. Use the lights during normal daytime hours, turning them off at night to give the plants time to rest. The halogen lights in combination with sunlight will be the most effective.
Supplement the halogen lighting with sunlight or fluorescent tubes, if possible. Because halogen only emits red light, you need a source of blue light for best growth. If you only use red light, the plants will be weak and leggy.
Add humidity to the soil and air for best growth. Halogen lights will dry out the air and plants need moisture to thrive. Touch the soil and add water whenever the soil feels like it is getting dry. Mist plants daily if they need humidity, like orchids.
Fertilize plants to give them the nutrients they need. Use food that is made for the type of plant you are growing. When all else fails, use a balanced blend with a 10-10-10 nitrogen-phosphorus-potassium ratio. Follow the application instructions on the packaging.
Watch for fungi or mold. Both may develop from the heat of the halogen bulbs. Remove moldy leaves and dispose of them. Leaving them in place will cause the mold to spread. Move the lights farther from the plants to limit this problem.