How low can you grow? The 1 Watt challenge
Good morning dear fellow growers
Last winter I decided to do an ultra low power experiment: Can you grow bell pepper plants using only 1 single Watt for the lights? Today I would like to share the surprising results with you.
On various hydro forums I got the impression that "more is better" regarding LED lights. People are using several hundred Watts for medium-sized tents. Because of the ongoing energy crisis, the cost for electricity has risen significantly, so we have to aim for maximum efficiency and the right dosage to keep our costs down.
A few thoughts came to my mind:
- The efficiency game is more or less solved imo. With LED emitters like the Samsung lm301b and lm301h evo, we're almost at the limit for white emitters, with over 220 lm/W if you underdrive them. Red/Blue LEDs would be even more efficient in theory, as the chlorophyll has two absorption peaks near 460nm and 660nm. But I have seen mixed results online. In most experiments I've seen, the white lights outperformed the red/blue ones using comparable amounts of energy.
- How do you get most of that light to the leaves? First, you obviously get the light as close as possible to the plant. Second, you want to use reflectors or optics. You want to lose as few photons as possible. Why don't more people use them? Other than prevent hotspots, I don't know.
I used this 7x lm301b star in 3500k, this driver, and this reflector. I measured 2.69V @ 350mA at the emitter, which gives ~ 0.95 Watts. As you can see in the pics, my whole setup pulled only 5.826 Watts. The air pump used ~ 2 Watts, the fan ~ 2 Watts, and the rest was power strips and the LED power supply. The grow tent was always closed in order to not distort the result (opened just for pics).
I managed to get the plant flowering, but for producing peppers, the 1 Watt appears to be too low in the end. The temp was much too low (17°C most of the time), next time I would rise it to get optimal conditions.
Posted Oct 27, 2022, 8:34 AM UTC · edited
This is extremely interesting to me. I figure you'd be able to grow salads with this easily?
Good idea, salads should be easy under 1 Watt per plant.
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