Tuesday, October 20, 2009

LED Grow Lights

As winter time fast approaches, the summer window sill season is coming to an end for many of the plants that require more light. This year however, I might be trying a new artificial lighting system, namely LED grow lights. Traditionally, Metal Halides (MH) and High Pressure Sodium (HPS) lights have been used as they have a high output of particular light frequencies which plants need.

As mentioned in previous posts, fluorescent lights typically do not have enough of an intense output to provide the necessary requirement for high energy plants like tomatoes. This means that if you are serious about growing, you will need to invest in a lighting system that will create the necessary lighting requirements for the species of plants.

But there are some drawbacks to these high output lighting systems. The efficiency of the lights themselves are relatively poor, which means a few issues coming to light. One is that the energy not being used for light is primarily turning to heat requiring some form of temperature control in the room to prevent scorching. This is exceptionally true for new growth plants. The other concern is the expense of having these lights operating. If you have a good size garden, say 50 sqft, you are looking at requiring a wattage of about 25W/sqft with 3 - 400 W MH lamps. If you are running this an average of 14 hours per day (16 hours during vegetation and 12 hours during flowering) this adds up to 16.4 kWh per day. Using the US national average for April 2009, this is roughly $60 USD per month. The fact of the matter, is that it adds up pretty fast.

Over the course of a year, that is nearly $750. Starts to make you wonder whether your tomatoes are really worth that much to you!

Why I am thinking of switching to LED Grow Lights

The first reason to go with LED grow lights is the control of the light spectrum used. Plants primarily use blue and red light for synthesis (hence the reflected green color). LED grow lights have the benefit of controlling this spectrum very well.

LED grow lights are exceptionally economical due to the efficiency of transferring energy to light energy instead of heat. LED's require approximately 75% less energy compared to MH or HPS lights. This would be an annual saving of approximately $500 per year.

LED grow lights also last significantly longer than MH or HPS grow lights. A Metal Halide light bulb typically has a rated life of approximately 15,000 hours and the High Pressure Sodium has about 25,000 hours. LED's on the other hand are twice as long as the HPS lights at about 50,000 hours of useable life.

Since the heat is exceptionally lower for the output, there is also less of a need for controlling the temperature of the room. This can also be additional savings with respect to air conditioning cost as well.

The growing results in studies speak for themselves. See this article on NASA and it's development for space farming with LED grow lights.

So, all things considered, I am thinking I might make the switch. I'll keep you posted.

Keep growing!