Specs for LED panel and estimated electrical costs

Several radish seedlings are now up in both flats. It's possible that the marigold seedlings are less leggy in the flat under the LED lights. I'll post a photo in a few days when the seedlings are a bit larger.

I checked the air temperature at night and it's about 63 degrees. That should be the same for both flats.

Here are the specs for the LED panel:

• Body material: Thermoplastic
• Circuitry board material: Diecast Chrome
• 60 Blue light LEDs: 465nm (nanometer) wave length
• 165 Red light LEDs: 650nm (nanometer) wave length
• 165 + 60 = Total 225 LEDs
• Color: Red + Blue = Purple looking to the eyes
• Working Voltage: 12V or 110V-220V
• Power: 13.8 Watts
• Dimensions: 12 ¼ inches (30.5cm) square
• Thickness: Low profile 1.25"
• Power cord length: 48 inches
• Recommended coverage: one panel per 18 inches square
• LED life: Approx. 15 years used all year long. (60 years for spring starting of seedlings)

I tried to calculate the approximate cost per year using the figures from my current electric bill. It comes to around $10 if the lights are on 12 hours per day year round. If three panels can replace one fluorescent fixture with two 40 watt bulbs, then the cost is roughly $30 for the three LED panels and about $50 for the electricity for the fluorescent fixture.

First seedlings and a temperature check

A few marigold seedlings are up in both trays and I can see both the radish seeds and the arugula seeds beginning to sprout. I'm amazed at how fast the seeds are germinating. At this point, there seems to be more activity in the flat under the fluorescent lights, but the difference is not great.

I just checked the temperature to see what sort of difference there was. The temperature in mid-day at the top of the soil in the flat under the fluorescent lights was 79 degrees, while that in the flat under the LEDs was only 72 degrees. This will certainly make some difference in germination rates.

Testing LED lights for plants

Since I couldn't find anyone who had actually tried the LED light systems I see advertised, I decided to try one out. I purchased a square panel of 250 LED lights, a combination of red and blue. The fixture is about 12 inches square and about an inch thick and weighs a pound or two. Here's a picture of it.



The color of the LEDs doesn't show up well. They really are red and blue. I supported the fixture by its corners with some empty coffee cans.








To test this for starting plants, I made up two trays of small peat pots with a seed starter mix and planted small marigolds, radishes, and arugula in each tray. I put one tray under the LED lights and the other under fluorescent lights, in both cases positioning the lights 5 inches above the top of the soil. I put them on timers for 12 hours of daylight. It's taken a couple days to fiddle with this to get the two timers pretty much synchronized.

Here's a picture of the setup.















So I have a race going. I don't have a control tray under no lights, but I didn't think of this until now. I set this up on Saturday, and I can already see the radish seeds beginning to swell.