LED grow light project

There has been interests about using LED light to grow plants indoor. There are also question about whether our light spectrum is suitable to grow plant. To put these arguments to stop, I have conduct a test to find out all the answers. I put two strawberry plants inside a closure space of Old TV cabinet. When door closed, there is absolutely no other light can get into this cabinet, the only light source is one of our Easy LED module running at 15 Watt.

 I have a timer set to light up this cabinet 12 hours a day to simulate real sunlight also.

I did some reading about general grow light, there are article saying the light need to be above certain strength to enable plant for photosynthesis instead of respiration. Our LED module emits a lot of light for illumination, for people to see things. But there is no comparison to strength of sunlight, which some time can burn your skin, and we generally don't want that kind of light strength in our house either.

But the purpose here is to grow plant, we we can shorten the length between light source and plants. I initially set the LED module fixed at top of cabinet, which is 25" away from the plants. I use a Lux meter and got 800 lux reading. Then I use two thin strings to lower the module to 16" above the leaves, my Lux meter read 2500 lux.  Since our module is so light weight, about 2 oz, it can be easily hang at desired height.

A TV studio only need requires 1000 lux of light intensity.  2500 lux is compare-able to sunlight of a overcast day.

At shorter distance, the light is much intense, too bright for viewing with general indoor ambient light; but it's perfect for growing plant.


The project is still on going, those two strawberry have been inside the closed cabinet for over 10 days by now. By compare photos from beginning and now, I sense that both strawberry have been grow bigger, healthier, with just LED light.

10 days after project started.

19 days after project started

Above photos shows 10 days/18 days after project started, the two strawberry looks bigger/taller and healthy; if the light doesn't work, these plant should be withered already.



You can order Easy LED kit at easyledlighting.com and specify LED modules to be unbent.

Is LED Light suitable to grow plants?

According to Wikipedia, suitable light to grow plants are: 
Natural daylight has a high color temperature (approximately 5000 K). Visible light color varies according to the weather and the angle of the Sun, and specific quantities of light (measured in lumens) stimulate photosynthesis. Distance from the sun has little effect on seasonal changes in the quality and quantity of light and the resulting plant behavior during those seasons. The axis of the Earth is not perpendicular to the plane of its orbit around the sun. During half of the year the north pole is tilted towards sun so the northern hemisphere gets nearly direct sunlight and the southern hemisphere gets oblique sunlight that must travel through more atmosphere before it reaches the Earth's surface. In the other half of the year, this is reversed. The color spectrum of light that the sun emits does not change, only the quantity (more during the summer and less in winter) and quality of overall light reaching the Earth's surface. The color rendering index allows comparison of how closely the light matches the natural color of regular sunlight.

The light spectra of different grow lights

Different stages of plant growth require different spectra. The initial vegetative stage requires a blue spectrum of light, whereas the later "flowering" stage is usually promoted with red–orange spectra. The reason: blue spectra are good to grow stem, orange spectrum are good to grow leafs.

The perfect LED grow light has controllable Blue and Yellow/Red LEDs, these special design LED lamps are usually more expensive. 

The other important factor is light intensity, a perfect grow light should give 1,000 but no more than 10,000 lux as compare to real sunlight. Many grow lights has adjustable height design for keeping perfect light intensity.

10,000 ~ 25,000 lux: Full sunlight, (not direct sun)
1000 lux: Overcast day, typical TV studio lighting
400 lux: Sunrise/Sunset on a clear day


Easy LED Lighting's natural white LED, which has energy concentrated at  3700 ~5000 K; but that doesn't mean there is zero energy at outside of this spectrum range, and it can certainly to grow plants. A cheaper way to enhance plant growing performance is to add (cardboard) panels painted in fluorescent blue and orange color at near the top, they can absorb reflective white light energy and emit blue and orange light. 

As for light intensity, Easy LED module can be easily adjustable hang to desired height to reach perfect light intensity.

To get Easy LED kits 
See LED Terrarium application