Halogen lights are plentiful, inexpensive and easy to find. Most people have halogen light bulbs in almost every light fixture in their homes. While popular for reading or other basic lighting needs, halogen lights are not the best light source to use for growing plants. Still, many people do use them as a light source for indoor growing rooms.
Set up your lights about 6 to 12 inches above the plant. If your plant has delicate foliage, set it at the 12-inch range. Halogen lights do not give a lot of output, so you will need quite a few lamps if you have a lot of plants. One lamp for two plants is the standard.
Add water and humidity to the air and soil. Halogen lights give off a lot of heat, so your plants are going to need watering more than if they were outside. If they are humid plants, such as orchids, be sure to mist them twice a day as well.
Supplement with natural light or florescent tubes. Halogen lights emit light in the red area of the spectrum. Because plants also need blue light to thrive (from natural or florescent sources), plants grown only under halogen lights will be tall and sickly.
Feed your plants. Sunlight provides nutrients that your plants will not get if they are grown only under halogen bulbs. Be sure to feed your plants a fertiliser based on the plant. If you are not sure, choose a basic 10-10-10 blend, which works well for most plants.
Monitor your plants carefully for mould or fungi. Again, the heat from halogen lamps can encourage mould and fungi growth. If you see spotted or mouldy leaves, remove them immediately and try moving the lamps further away from the plants.
Consider purchasing specially-made grow lights. While more expensive than halogen light bulbs, they cover every range of the light spectrum that plants need to thrive.