Indoor Grow Lights – Demystifying Fluorescent, HID, HPS, MH and LED

Indoor grow lights are used when the ambient light available to your plants isn’t sufficient for them to survive or grow nicely. This would be the case if you have a grow room that you use to grow lots of plants that normally would need direct or indirect sunlight.

Grow lights are special kinds of lights that produce light in a spectrum that plants use.

Which brings me onto what colours of light plants use. Different colours of light are used for different stages of a plant’s growth. In the initial growth stage, plants make use of blue light. In the later flowering stage they need orange to red light.

Plants don’t make use of green light, so there’s no point in providing it. So purpose-built grow lights don’t waste energy producing unnecessary light that plants don’t use.

When looking for grow lights for your indoor garden, you’re faced with quite a selection in terms of what lighting technology you would like to use.

The main types are:

  • Fluorescent
  • HID (high-intensity discharge)
  • LED grow lights

Fluorescent grow lights are easy to obtain, available in different shapes and sizes, including compact fluorescents (like energy saving light bulbs, just specifically designed for plants). They’re also fairly affordable.

High-intensity discharge lights are used by commercial growers and more serious home growers. They are more efficient and come in the form of HPS (high-pressure Sodium) and MH (metal halide) lights, each geared more towards a specific stage of plant growth.

Finally, LED grow lights (or at least the ones that work well) are fairly new to the grow light scene! They’re energy efficient and have a longer lifespan than the other two categories of grow lights.