I showed my current hydro lettuce setup in a previous post. I want to explore setting up the optimal LED setup for growing just one leafy plant.  My current setup can hold up to 9 plants.  Most setups I have seen wish to accommodate many more than 9.  I’m interested in starting with one and adding as needs expand.  Is there an effective and efficient way to build an LED setup for leafy plants in which it starts with one and then incrementally adds on more?

In this post I explore part 1 of building an LED setup for one lettuce plant. – the LEDs.  Once I am able to test it out, I will consider a future effort that connects single LED systems together to support more lettuce plants.

The Goal

The goal of this post is to review the circuit design of a single LED setup for growing lettuce.

Let There Be Light

Blue And Red

There are several lighting technologies that I could choose from.  I choose LEDs because they are effective, efficient, becoming more and more affordable, and researched.  My current design uses a white and red LED.  For this LED setup I will use blue and red LED lights.  Blue and red lighting is known to be effective for enhancing photosynthesis.

The photosynthesis process of leafy plants respond to blue and red light at the following wavelengths:


My LED choice will be based on the wavelengths:

  • Blue: around 430-455nm range
  • Red: around 635-640nm range
I will use LEDs that are close to these wavelengths if they are good quality and easy to obtain. 

Manufacturer And Part

I chose Cree LEDs because I wanted to start with “the best” to avoid variances in results because of lower quality.


For red I will be using what I already have, the XP-E2 3w red LED (data sheet).  Since the XP-E2 comes in a variety of wavelengths, the image below shows the red along with the other LED offerings:

Red Wavelength
The red wavelength is slightly lower than idea at a little more than 630nm, but close enough.


I will be using the royal blue XT-E2 LED:
The royal blue wavelength seems to be within the ideal range.


I chose to buy in quantities of 6 from LEDGroupSupply.com (links red and royal blue).  I have been happy with previous purchases.  While I haven’t done much research at this point on sourcing, I assume the prices paid are at the high end.  Since this is testing I am opting for time, quality, and piece of mind.

That’s it for now.  Thanks for reading this far.  Please find many things to smile about.