Introduction: Growing Plants With LED Lights

In this instructable i shall be demonstrating how to grow small plants under the glorious glow of LED lights. Woop!

Step 1: Introduction

First and foremost...Hullo!!
This is my first instructable (long time reader, first time "actually-post-anythinger", i should be revising for exams, hence i have done this instructable!), any comments and criticism is greatly appreciated.

This instructable will demonstrate how to grow small plants under LED lights.
The idea for this came from an odd source, a friend of my step fathers recently had to run away to a different country because he was caught purchasing large quantities of lights from electrical stores for growing some none-too-legal plants indoors.
I don't condone this in any way, by all accounts the man was an idiot. But it got me thinking about ways to grow plants under artificial lights,after a bit of thinking and a lot of googleing this project was born!

A bit of theory:
Plants look green, therefore they reflect green light, so it probably isn't used in photosynthesis or any of the other interesting things plants do.
So hopefully by using red and blue lights (the colours either side of the spectrum from green) we should be able to keep plants happy and use less energy because where not producing green light which would just get reflected.

(apologies in advance, i cant seem to be able to get the image tag thingys to work, i will try and explain images as best i can.)

Step 2: Materials

This instructable assumes you have experience with soldering, and have some basic knowledge of electronic circuits. There are instructables elsewhere that should be able to teach you some of this stuff.

Things you will need:

A Tub (Twiglets not required, but reccommmend on grounds of deliciousness)
A smaller tub to grow things in.
Tissue Paper
Strip Board
High Brightness Red LED's (number depends on size of tub and brightness, try some experimenting)
High Brightness Blue LED's (you'll need fewer of these.)
Misc. Seeds (Experiment with different kinds. cress works well)
220 ohm resistors
A power supply (A bech top variable one is highly recommended, although others will work)

(apologies for the shocking quality of the photos. i'm a poor student and cant afford a decent camera)

Step 3: Construction: Soldering the Leds

There are a couple of ways to do this, in past experiments i have just drilled holes in bean cans/tubs then glued LED's in place and wired them up by soldering wire between each one.
In this incarnation i have chosen to build 3x3 LED "modules", in the image below is a very quickly scrawled diagram of how the LED's are wired on the pieces of strip board.

Once each module has been built they where wired in parallel to the power supply.

.......i wish i was better at explaining this.
basically, as long as you have enough light coming from the LED's and you are comfortable with the way they have been wired, and most importantly nothing explodes or smells funny you should be ok. It's pretty simple really.
Whatever you do, don't forget to include some form of current limiting resistor, if the first year and a half of my electronics degree is anything to go by, they seem rather important.

With the size of my tub i chose to use a 3 3x3 LED modules, giving a total of 27 red LED's, and only one blue LED.

Why only one blue LED??
After a bit of googleing sometime ago i stumbled on a (i think) NASA project to do with growing plants under LED's, and they said you need a lot less blue light than red, and a biologist friend of mine confirmed this....and that is why there is only one blue light.

Step 4: Construction: Erm.....constructing It!!

This step is fairly straight forward.

Take the glue and haphazardly glue the LED's to the lid of your container of choice then plug it into a power supply and hope nothing blows up

(DISCLAIMER: its not my fault if anything blows up.)

when nothing does blow up let out a sigh of relief and relish in the futuristic glow of your new LED grow light system!

(Note on voltages: for the set-up i'm using i found that 7 volts was adequate to light all the LED's and for nothing to get too hot, and for the current consumption to be adequate. YMMV. i strongly suggest using a variable power supply to find the optimum voltage.)

Step 5: Using It

Now for the best bit, actually using it.

1.)Place the tissue paper in the small tub and dampen with water, then sprinkle a few seeds ontop and place inside your LED growing tub.

2.)tun on.


4.)eat delicious plants!

depending on what your growing you may need to transplant the seeds into a better growing medium once they have germinated.

During my first attempts at growing plants under LED lights, i grew cress in a bean can, and used a PIC microcontroller to turn it on and off every 12 hours, this produced failry good results, the cress grew quicker than some placed on my windowsill.
After reading around a bit on the internet (whether you agree with the use of a certain herb which is currently illegal in the uk or not, the people who grow it tend to be very knowledgeable on plant cultivation, and have a wealth of experience in growing plants under artificial lights) i found talk of keeping lights on for 24 hours during vegetative growth stages, then encouraging flowering by switching to 12 hours on and 12 hours off during, i don't know if this applies to all plants, but i shall be experimenting.

I'm still playing around with this so any suggestions/improvements are greatly appreciated, and if anybody decides to do this themselves (i hope you do, its great fun) i would love to hear about your results.

Step 6: Update! Thigns Have Grown.

Below is a photo of a little spinach sprout that has been germinated and grown a few leaves using the LED lights.

Having sprouted a few plants using this system i have transplanted them over to some compost on my windowsill as I didn't think my bench top supply would be too happy running 24/7.

I've picked up some odds and ends today now my student loan has come through, so hopefully within the next few weeks I'll have a larger system set up with 3w LED's and some nice microcontroller control, and quite possibly an instructable documenting it all.