Grow Lighting – Artificial Plant Lights

Grow lighting refers to artificial lighting, which stimulates plant growth. It is needed when you have plants that need direct sunlight but don’t get enough of it.

A grow light is an electric lamp designed to emit light in the colours required for photosynthesis. This is typically blue and orange to red light. Green light is not needed for photosynthesis.

Do I Need Grow Lamps?

If you want to grow plants that require direct sunlight indoors, but you’re not able to put them somewhere where they get direct sunlight then the answer is yes!

Light Colours

It’s import to understand the colour or spectra of light required for plants to grow. Different colours of light are suitable for different stages of a plant’s growth. The initial stage of plant growth needs blue light while the later flowering stage needs orange to red light.

Dark red light causes tall plants. Red and blue light produce shorter plants.

Types of Grow Lamps


These are ordinary light bulbs and aren’t great as grow lamps. The light they emit is too red. Plants also require blue light. You can use them to provide decorative lighting for your plants. They consume a lot of energy.


Fluorescent lights, including modern energy saving light bulbs can be used as grow lamps as they emit quite a broad spectrum of light. Some of these are sold as special grow lamps, but it doesn’t mean that they are much better than those commonly available.

It may be worthwhile to combine two fluorescent lights together — one with a warmer light and one with a cooler light to expand the spectrum even further.

HID – HPS and MH

HID (high-intensity discharge) lamps have traditionally been used as grow lamps. Often HPS (high pressure sodium) lamps, which supply orange/red light are used in conjunction with MH (metal halide) lamps, which supply blue light. Together they provide plants with the light they need to grow.

HID lamps require “ballasts”. These are electronic devices that help start a light and prevents it from overheating. Digital ballasts will increase the lifetime of your grow lamps.

LED Grow Lamps

LED grow lamps are the newest kids on the block. They are very promising for use as grow lights because they are very energy efficient, do not generate much heat and have a long lifespan.

Light Placement

Lights should be placed very close to the plants. As the distance increases between the lights and the plant, so the intensity of light decreases. If the lights are generating a lot of heat, don’t put them so close that they will burn the plant’s leaves.

It’s also a good idea to make maximum use of the light you are producing. This means using reflective material to direct the light over the plants. You can also use a reflective paint (e.g. white) on the walls of your growing enclosure, if you have walls.

Exposure Time

Most plants require a lot of light to grow. 12 to 18 hours of light per day is typically needed. Don’t leave the lights on all the time. Plants need darkness to grow, so switch them off to give the plants a break.