Growing the bright way – How to select a LED grow light

Published on February 15, 2015, by in Tools.

LED grow lightLED grow lights are instruments that supply artificial light to plants to stimulate photosynthesis. They emit an electromagnetic spectrum which stimulates plant growth. Grow lights are essentially used when the plant cannot get enough light (like in winter) or when the plant requires additional light. These lights can supply the plant with a few more hours of light it requires to grow.

LED lights were first used as indicator lights and are now used for a wide range of purposes. Although LED grow lights are the most recent type of lamps to be mass produced, its use is not very popular among the consumers. This artificial light source can greatly benefit your plant during every stage of its growth.

There are some key factors to take into consideration when searching for the best LED grow lights for your plants.

Chip Wattage

Studies suggest that the most efficient wattage for LED chips is 3 watts. One watt chips are the most stable and have a longer life but do not provide enough power to deeply penetrate the plant’s canopy. The price of the chips increases if chips of a higher wattage are used. Many people have had great success using 5 watt chips which are slowly becoming cheaper and cheaper with advancement in technology. Even though the 5 watt chips provide more power, the 3 watt LED chips have the perfect balance between size, heat emission and cost and efficiently penetrate almost 5 feet of the plant canopy.

However, it is important to note that the actual output provided by LED lights differs by 50-75 percent. Some companies do not power diodes to full capacity. It is therefore important that you know what the actual wattage of the chip is when viewing the specs of the LED grow light.


LED lights made with metal bodies are much better than those made with plastic bodies. Unlike plastic, metals such as aluminum are good conductors of heat and absorb the excess heat which would otherwise melt the plastic.

Preference must be given to grow lights that have a constant-current driver over the ones that have a constant voltage driver. The voltage of the LEDs will fluctuate as they get warmer. Having a constant-current driver will maintain the current hence extending the life of the diodes.

Coverage Area

The square footage of the area you want to cover will determine the size of the grow light that you choose. An area of around 4 square feet will require a small light where as an area of 25 square feet will require a large light. Sometimes choosing a large light can be more beneficial. It falls cheaper and the light can always be moved back if the radiation is too intense for the plant. Along with the size, the angle of light is also an important factor to consider. An angle of around 60 degrees provides more power to grow but reduces the coverage area. A less acute angle, say 90, degrees covers a larger area but the intensity of light reduces. An angle of 78 degree delivers an almost perfect combination of power and intensity.

Cooling System

It is always better to choose LEDs with a metal core printed circuit board. They have a metal heat spreader which runs the chips at lower temperature, extending the life of the LED. Commercial, greenhouse and Research grow lights do not require internal cooling fans due to their design. Other LEDs require internal cooling fans as LEDs give out 80% of its energy as heat.

Keeping these few things in mind, when purchasing a LED grow light, will ensure you get it totally right.

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