Introduction: Green Thumb Grow Lights

Picture of Green Thumb Grow Lights

To quickly and efficiently grow plants from seeds I built a simple and low cost LED grow light kit . I used a plastic storage bin to support the LED strip lights and to provide a moist environment during seed germination and early growth. After the seedlings reached a healthy size they were transferred to the garden for the summer.

The figure above shows that plants absorb light for photosynthesis at blue (~ 450 nm) and red (~650 nm) wavelengths. For a typical incandescent light bulb most of it’s light energy is in the infrared spectrum and is wasted.

For my seed starting kit I selected the Gled® red-blue LED grow light strips that are energy efficient and super bright. Additionally, the measured light strip spectrum matches the wavelengths that plants absorb during photosynthesis, promoting efficient and optimal plant growth.

Growing plants from seeds allows you to choose heirloom, organic (not genetically modified organisms) and unique plants that are not easily found at nurseries. Growing your own plants and vegetables promotes healthy living and is fun!

Step 1: Materials and Tools

Picture of Materials and Tools

Here is what you will need for the project:


  • Gled red-blue LED strip lights, ~$30 / 5 strips
  • 12 volt power adapter, 6 amp, ~$8
  • Timer, ~$5
  • Large plastic bin, ~$6


  • Jigsaw or small hand saw
  • Soldering iron


  • Soil
  • Seeds

Step 2: Cut Openings in the Plastic Bin

Picture of Cut Openings in the Plastic Bin

The first step is to cut openings in the plastic bin to hold the LED light strips and to provide for cross ventilation.

Cut 5 evenly spaced rectangular openings (slightly larger than the light strip cross-section) near the bottom at each end of the bin. These openings will hold the LED light strips in place without any glue or tape.

As shown in the above figures, cut two large openings (mine are ~6 x 12 inches) to provide for side ventilation. During seed germination I covered the openings with plastic wrap. Once the seeds sprouted I removed the wrap to provide for cross ventilation.

For a clean cut, I outlined the desired opening with tape. I used a jigsaw to cut the openings, but any fine toothed saw will work. The side ventilation openings have rounded corners to make the cutting easier.

Step 3: LED Light Strip Wiring

Picture of LED Light Strip Wiring

The LED light strips come pre-wired with small connectors on each end.

You can connect the strips in series, one to the other, however I found that the first light strip became fairly hot, given the amount of current flowing through it.

It is best to break the light strips into two groups to reduce the current (and heat) of the first strip. I connected the power adapter separately to groups of 2 and 3 light strips. This way the total current is split between the two light groups, avoiding overheating issues.

I used a soldering iron to attach jumper wires to the power adapter and attached small lug connectors to these and the LED light strip wires. If you wish you can skip the lug connectors and solder the jumper wires directly to the LED light strips.

Step 4: Assembly

Picture of Assembly

Assembly is easy, simply slide the light strips into the bin openings and connect the jumper wires as shown in the above photos!

Step 5: Seed Growing Process

Picture of Seed Growing Process

Select your seeds from a variety of local or internet suppliers.

Plant the seeds in seed starting soil, which has been sterilized to prevent fungal growth.

Seeds germinate within 1 to 3 weeks depending on the seed type and should be kept warm and moist during germination.

After seedlings emerge, most require 14 to 16 hours of direct light to produce healthy stems and leaves, which can be controlled by adding a simple timer.

As the seedlings begin to outgrow their container, they should be thinned and transplanted into larger pots.

Step 6: Results

Picture of Results

To measure the performance of my grow light kit I planted two basil seed trays. One tray was placed under the grow lights and the other was placed near a south facing window.

About one week after germination, as shown in the the above photos, the seedlings under the LED grow lights were strong and leafy, whereas the ambient light seedlings were a bit spindly.

Step 7: Plant Choices

Picture of Plant Choices

Growing plants from seeds allows you to choose heirloom, organic (not genetically modified organisms) and unique plants that are not easily found at nurseries. Common and unusual plants that interest me are:

Common Plants

  • Cucumbers
  • Tomatoes
  • Peppers
  • Zucchini
  • Basil

Unusual Plants

  • Large Bottle Gourd
  • Rouge Vif d’Étampes (Cinderella pumpkin)
  • Baby Bok Choy
  • Asparagus Beans
  • Cinnamon Basil
  • Viola Sororia Freckles
  • and many more…

Step 8: Summary

I designed and built a low cost (< $50) LED grow light kit to grow plants from seeds that is simple and fun to use.

The blue-red LED light overlaps the wavelengths that plants absorb during photosynthesis promoting efficient and speedy plant growth.

Growing plants from seeds allowed me to choose interesting vegetable plants for my garden that were not available locally.

I hope that you enjoyed reading my LED grow light instructable!

Thank you, GreenThyme


QuintenC made it! (author)2017-04-27

I made this and I am happy with the results. I have not started planting seeds yet, but I will this weekend. I dont have a hot glue gun, but I will be getting one before I start planting.

MoonAndLion made it! (author)2017-03-26

I used a different set of lights that came pre-wired with a power supply and some hot glue, but it's working. Total project cost ~$30 USD (for lights and container). Total assembly time ~ 1 hour.

Thanks for the Instructable!


Tsu Dho Nimh (author)2017-03-12

Nicely thought out, and it would keep the @%!@#$* cats out of the plants.

If you want to sprout even more things, try soil blocks. I experimented with setting the seedlings out when they had 3 or 4 true leaves, and it worked very well. They have less transplant shock than larger seedlings would.

MarinaK14 (author)2017-03-08

This is genuis!!!! Can I try this for tomatoes or would I need more light?

Tsu Dho Nimh (author)MarinaK142017-03-12

Marina - you can start the tomato seeds in this, and keep them until they are a few inches tall. After that they need to be outside with real sun.

JobB made it! (author)2016-03-30

I just finished building mine. Thanks for sharing. Great idea and perfectly worked out. Simple and cheap.

The basil experiment did it for me.

Question, how much power do those Gled strips draw? I have some pimp-my-ride-BS-under-the-car-strips (15 * LED(1210)per strip * ( 4 strips red + 4 strips blue ) * 0.08W/ Led) = 9.6W. Do you think that's similar to what you have? I see people blasting 100 W in their plant. Is that overdoing it?

Thanks again!

Thanks again.

JobB (author)JobB2016-03-30

Sorry, this question was asked below.

Answer by GreenThyme (author): My strips require 12v and consume approximately 28 watts total.

BNA15 (author)2016-02-16

Thank you very much Thank you for sharing this project! You gave me the information and encouragement...........................................................................................................

EvanW13 made it! (author)2015-12-29

Thank you for sharing this project! You gave me the information and encouragement I needed to give this a try. I built a slightly modified version and am very pleased with it. I love starting plants for my vegetable garden each year and may end up building several more of these so I rigged an old computer power supply as the driver for them so I can run five or six off of the same supply. I also used a taller (112 quart) storage bin and mounted the lights on the lid to see how that will work out.

dianadfonseca (author)2015-11-08

Thanks for sharing!

mchambers5 made it! (author)2015-10-01

Just finished this little project! Planted some low space cucumbers and some dill weed. Will see how that goes

simofo (author)2015-09-17

Hi, unfortunately the "Gled" Strips dont ship to my country.

Would these also work?

They are specified with a Power Dissipation of 14.4W /M

and Input Current 600mA /M

Thanks for nice idea :)

GreenThyme (author)simofo2015-09-17

It looks like it should work!

Good luck!

simofo (author)GreenThyme2015-09-19

I found much cheaper ones at aliexpress with free shipping to germany

16€ for 5m waterproof

only question is how to stick them permanently to the grow-box..

MorNiLachnan (author)2015-09-17

Can you explain how you split the wiring? Did you just wrap the two positive wires from the light strips to the end of the positive wire of the driver? I wanted to run 2 sets of 10 strips, any idea what the specs should be for the driver? Wasn't sure if any 12v driver will do or if it needs to have a specific capacity (watts, amps etc)?

GreenThyme (author)MorNiLachnan2015-09-17

Yes, everything is wired in parallel. The positive wire from each set is connected to the power supply positive wire. My strips require 12v and consume approximately 28 watts total.

In your case with 20 strips a larger power supply (12v with at least 10 amps) will be needed.

Good luck!

ecjones (author)2015-09-17

Really like this, where did you purchase your lights? Post links if possible please

GreenThyme (author)ecjones2015-09-17

I bought the Gled lights on Amazon. This is the link:

Have fun!

toz1 (author)2015-09-15

Excellent idea

laith mohamed (author)2015-09-14

I like mixing nature with electronics so i like your work and go on.

uncle frogy (author)2015-09-13

nicely done a little finish details like hiding the wiring and it looks like a commercial product

uncle frogy

GrumpyOldGoat (author)2015-09-13

I understand the red-blue combo, but does UltraViolet or infrared figure into the plant needs?

FlorinJ (author)GrumpyOldGoat2015-09-13

UV actually harms many plants and reduces growth, while others don't care. I don't know of a single garden plant which benefits from UV. Some level of UV might be beneficial, though, the same way as a small amount of microbes in our environment helps keeping our immune system on its toes.

IR is thermal. Could make use of the thermal radiation to warm your plants if the surrounding air is too cold. Other than that, if the air is too hot, additional thermal radiation can only be damaging.

GrumpyOldGoat (author)FlorinJ2015-09-13

I which case I shall leave them out of the strips I am building to build your AWESOME Instructable.

I'm also going to build one of the 'space saving' vertical hydroponic system and this lighting should be perfect.


grannyjones (author)2015-09-13

My son germinates seeds in a cooler with jugs of hot water below the trays of soil. Then the seedlings get moved into the light.

williamjones (author)grannyjones2015-09-13

Cool, grannyjones, how does he keep the water hot? Does he just fill jugs before night time with hot tap water or what? Thanks, grandpajones

Zamperweenie (author)2015-09-13

This is pretty cool! I like it. You could even consider adding in an Arduino and a cheap LCD screen to add some functionality to it (temperature, moisture, how long the lights have been on, etc.). The programming for this is minimal, but the reward is high! Very cool though.

Nighthaw (author)2015-09-11

you had mentioned keeping the seeds warm as well, hire did you accomplish this

impied (author)2015-09-10

This is awesome! I want to try this, the plants I start from seed never seem to be that happy to grow. Where did you buy the hardware?

GreenThyme (author)impied2015-09-10

I bought the LED strip lights, power adapter, and timer from Amazon and the plastic bin from Walmart.

Good Luck!

jOker58 (author)2015-09-10

if your going for adorable that's great but I think its very functional and advanced

brandonbabeh (author)2015-09-07

Oh, that's so cute and doable!

robo_light (author)2015-09-06

Great idea! Thanks for sharing.

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