Introduction: Small Indoor LED Plant Grow Room

Picture of Small Indoor LED Plant Grow Room

I have done a few indoor gardens before, mostly because the weather in Michigan does not allow for a very long season. I recently moved to Phoenix and tried container gardening outside and was disappointed in the amount of pests that decimated my small container farm. So here is my take on a very small indoor LED garden to see how it works out.

Step 1: Parts & Tools

Picture of Parts & Tools


  • Cardboard Box
  • LED Light
  • Aluminum Foil
  • Spray Adhesive


  • Box Cutter
  • Scissors

Step 2: Line With Reflective Surface

Picture of Line With Reflective Surface

I chose to line the box with aluminum foil because it is highly reflective and can act as a water barrier. I overlapped all the corners so that if water does spill in the box it won't ruin it. The spray adhesive is easy to apply and sticks strongly to the box.

Step 3: Cut Out Light Hole

Picture of Cut Out Light Hole

Cut out a hole that will allow the light you have penetrate into the box.

I am using a light that I created in another project to shine into the box. It just sits on top of the box and has a fantastic coverage. The heat created by the lights can radiate up and you can easily lift up to check on your plants.

Since my light covers almost the entire top of the box I cut a hole in the entire top except for the side with a flap (left an inch or so) and the corners to keep some strength in the box.

Step 4: Add Plants, Fertilize, Grow

Picture of Add Plants, Fertilize, Grow

I started some seedlings in a small starter tray then transferred the plants to small pots. I also used the flap that I cut out as a lifter to get the plants closer to the light before they mature.

I use a hydroponic fertilizer to keep the plants growing strong. This is essentially the same thing as doing a hydroponic setup but using a sterile grow medium that looks like soil. I water every day based on the provided feeding schedule.


bluenail (author)2015-03-26

Hi. I'm planning on building a growbox for my chilli plants and for lettuce. I've been looking at both your design and one by OKGrowin which uses much stronger lights.

OKGrowin suggests that LED strip lights might be too lacking in penetrative power. Is this something you have found?

How hot does the heatsink get? Can you comfortably put your hand on it? Also, how much power does the whole thing use? You've got about 3m of LED strip, right? How large is the cardboard box? Do you think it is too much, not enough? Is there anything you would consider changing if you started this project again?

Sorry if I have missed the answers to these Qs in the text somewhere.

GeorgR (author)bluenail2015-10-25

I honestly don't understand why people go through the effort to DIY LED lights, EXCEPT if someone would have custom requirements for LEDs. Because 300W LED lights you can get for $65 shipped if you look on ebay. I am currently growing Chillies with two of such lights. And those 300W lights have red/blue and a bunch of whites. Nothing "fancy", but's just a grow light, not rocket science.

tgvoss (author)GeorgR2015-10-27

GeorgR, People that use this site like to DIY things. I am sorry you like to just buy everything but that is not what the community at instructables is about. I also like to do very simple projects with a very little budget. $65 is not anywhere close to the $25 light I created that happens to also be useful for other things in my life. That is why I DIY. It may not seem like a difference to you but it is to me. If you don't have constructive criticism to share please keep it to yourself.

tgvoss (author)bluenail2015-03-26

If you are worried about not being enough light try these out. They are brighter than the ones I am using and have a built in aluminum backing which is more effective at dissipating heat.

I have been growing herbs just fine with about 8m of 5050 style strip lights in a 14"x14" box. The heat generated by these lights is negligible, especially when hooked up to a voltage regulator (45'C). I can touch the aluminum mount easily with no worries. Without the regulator they get a little toasty (52'C).

If I were to do this again I would use a mix of warm and cool white 7020 on aluminum to add a larger growing spectrum and better heat dissipation. I have been pleased with the growing results but have heard this can bump growth even more.

bluenail (author)tgvoss2015-03-27

Sorry to bother you again. Are you using a different power supply to when you used the lights for the seedlings? I'm not an expert (barely a beginner) but the one you linked to maxes out at 72W and 8m of lights (5050 or 5630?) goes beyond that.

tgvoss (author)bluenail2015-03-29

Yes, used the same 6A 72W power supply. If you want to use 6530 you could get a larger power supply but you are getting more light and could probably use less lights. In general I have found that these cheap strip lights draw less power than they claim so you should be fine.

bluenail (author)tgvoss2015-03-26

Thanks for your reply. I was also planning on using a mixture of cool and warm whites - possibly set up so that I can adjust the ratio as I go along. My budget is fairly low, and I don't want to make too much of a dent in the monthly electricity costs.

I saw the 7020s mentioned in the comments, but I haven't been able to find much information to compare them with the 5630 flexible strips I was looking into before.

PetervdPol (author)2015-03-26

Just to add to the discussion: in professional greenhouses the ratio blue/red is 2/1 or 3/1 There is also an interesting effect of far-red (730-740nm) which gives you longer internodes on a couple of varieties. The interesting thing is that you only need 10-20 minutes of far-red at the end of the day (google EOD LED) followed by a couple of minutes of red (660nm) to give you the longer internodes.

tgvoss (author)2015-03-11

Here is a side by side comparison of seedlings from the same initial tray. Same fertilizer and water schedule, different lighting (14hrs of LED) and environment (February in Phoenix, AZ, USA ~ 12.5 hrs of sunlight).

diy_bloke (author)2015-03-11

Your design is so simple that I didnt even think of it myself. I was struggling with wood and polyurethane plates till I saw yrs and thought "yeah".
Fairness bids though to say my plans were for something i could also use outside, but for now I just settle for the carton.
I have a 5 watt growlamp (LED) in it and though that might not be enough to let the plants go to full development, but quite enough to rear seeds till I can put them outside.

SophiesFoodieFiles (author)2015-03-10

This is so cool! :)

tgvoss (author)2015-03-02

A quick update, two weeks after transplanting I was able to harvest lettuce and basil for dinner. (two weeks to grow the seedlings in the starter tray from seed)

Elac. (author)tgvoss2015-03-10

That's great to hear, plants look really nice.

What type of basil and lettuce are you growing?

tgvoss (author)Elac.2015-03-10

Sweet Italian Basil, and Black Seeded Simpson Lettuce

aperkins01096 (author)2015-03-02

I've used both red/blue combination and white LED's for growing lettuce and tomatoes, found little if any difference. White off the shelf LED bulbs are easier to find, and wattage wise are comparable.

steven4872 (author)2015-02-24

As to the comments about plants doing bast with red and blue LEDs. I have found that is true for some plants others that is not true. I have several orchids that haven't done well due to insufficient natural light (my windows are shredded to much). Several haven't bloomed in years. I built a grow lamp using red and blue LEDs. The orchids had great root growth but little to no leaf growth.

I tried some old incandescent lights i had and got results that were a bit better. So I built a new grow lamp using 2700K white LED and supplemented with 660 red and 465 blue (one blue and red for every 4 strips of white). three A couple of months after building the lamp 3 orchids sent out flower shoots. Two of those hadn't bloomed in at least 4 years. In contrast some snapdragon and columbine plants have done very well under the red and blue grow lamp. The power consumption of the white LED lamp is about the same as the red and blue lamp.

I have read about a experimental green house that was made with transparent solar panels that absorbed mostly green and yellow light while allowing red and blue to pass through and reach the plants. The idea was to make a green house that generated power as well as food. Many of the plants did well but some didn't. Many plants have pigments to guide growth. Some pigments are not strictly sensitive to red and blue. I suspect that pigments other than chlorophyll are why some plants don't do very well under red and blue grow lamps.

tgvoss (author)steven48722015-03-02

I think for people interested in blooming Red/Blue supplemental lights are helpful. Since I am growing Lettuce and herbs that I do not want to bloom, not having intense red/blue light is helpful in keeping them from blooming.

smeyer7 (author)2015-02-12

Very nice project!
You kept it simple, quick and easy!
But the LEDs you have taken are really inefficient for plant growing, Photosynthesis has its peaks by royal blue (~480nm) and deep red(~650nm) light, the benefit of using an LED grow light is that you can buy LEDs in exact these wavelengths, to provide the most efficient grow...
keep on building!

tgvoss (author)smeyer72015-02-12

Yes, I am aware that many are experimenting with Red/Blue combination setups. To date I have remained skeptical of the actual growth output of these DIY Red/Blue setups using cheap components. I know $2k+ setups seem to have nailed it but it is not economical for a home grower to use them at this time. This 5000k light puts out more light per watt than a CFL setup and it is much cheaper to build. Oh, and you don't need special glasses to check your plants.

MatB1 (author)tgvoss2015-02-17

The assumption that red + blue LEDs will be better has been around for a considerable time. I previously built quite a large two-level hydroponic grow pod with about 350W of red and blue LEDs that were cooled by the hydroponic fluid.

Then I decided to do more research because it was quite clear that total light output from white LEDs is much much higher than monochrome LEDs. It's true that there are peaks in photosythesis activity at red and blue but it's not a case of the rest of light, even green, from going to waste. So I rebuilt the rig with around 220W of a combination of warm and cool LEDs. Nutrient uptake (and hence growth) was around 10% higher. These results are in line with some others also. Essentially white LEDs are *much* better for growing plants.

smeyer7 (author)MatB12015-02-24

Nice experience report, do you have any Dokumentation about it? which Plants did you used and how did you measured the groth? Oh and did you used warm white or cold white LED's?

Or any Links for Informations? i'm Curios!

Sure the Lumen output of white LEDs is much higher, but Lumen is only an Unit how bright the light seems to the human eye...

I want to buy a new Plant LED and before this post it was totaly clear to buy an Red/Blue Setup... but now i'm undecided to buy a simple white led instead...

MatB1 (author)smeyer72015-02-24

Hrm yes, but I can't find it on Google+. I'll have a longer look later.

As I said, I measured growth by hydroponic nutrient uptake. Also as I said, I used a combination of cool and warm. About 60% warm, 40% cool.

I didn't say lumen output I said output. It's a plain question of efficiency. Blue and red LEDs just aren't very efficient. That is the main problem. Also, there's two types of red LEDs, one is higher frequency than the other and quite a bit more efficient. The wavelength is too high to reliably promote flowering. The deep red type will, but is much much less efficient. Many cheap growlights use the cheaper more efficient ones. Growlights that use the deeper red LEDs are seldom bright enough.

Mj_monsion (author)tgvoss2015-02-13

I have personally seen a homemade red blue led light setup with phenomenal increase of growth that only cost 75 bucks.

tgvoss (author)Mj_monsion2015-02-13

What was being grown? What skills were needed to make it?

This entire setup is made to be easy to build and fit into a small area.

Akin Yildiz (author)2015-02-21

maybe this will clear away some doubt about the choice of light spectrum.




i've designs using only white, only yellow, only red, only blue or mixes - they all work. the difference is the type of plant and what you are trying to accomplish with this plant. also one thing to note here, these led strips may not be as strong as high power leds. these 1W @350mA are the "weakest" high power leds in the family. you can go 3W, 9W even upto 100W without the size of the led changing. high power leds require very stable cooling systems. either manually with a proper heatsink or with the aid of fans.


thank you for sharing, very nice minimalist setup.!

OliverK1 (author)2015-02-21

Why white LED? Plants only use certain wavelength.

tgvoss (author)OliverK12015-02-21

Check out the comments below...

frajerry (author)2015-02-17

Very nice project. Just a small idea

would not be more reflective a white wall instead of the metal (grey) one?

tgvoss (author)frajerry2015-02-17

I used tin foil, the idea is that it reflects the light back to the plants. A few have suggested white paint instead of foil because it disperses the light more evenly. I may try that in the next version.

cantinora (author)tgvoss2015-02-20

I am going to second using white paint. Beside the even dispersal of light (as white reflects all color) the foil is nearly impossible to get perfectly flat, and anywhere it's pinched or folded will create a laser beam of heat right at your plants. I, too, used foil for indoor growing during winter.... Then I had a lot of holey plants. Not good...

ruthh2 (author)cantinora2015-02-20

I was lucky enough to get mirrored wardrobe doors a few years back. Had tried foil and white paint with grolux lights in my cellar to plant out in my tiny yard, with some success but leggy plants. as i have moved house and now to a large garden, i need more early propagation space. the mirrors came with me. now i have a large propagator, and my last groluxlights need replaced. i will be trying a mixture of cool and warm leds. i have found this best for anything i need good light for, eg, embroidery, dog,grooming. either alone seems to distort colours and lead to headaches as your eyes adjust. a mixture is just right and can be tailored easily with the range of led's now available. And my 6 x 3 foot propagation space will now be using around 50 watts instead of 1200, so I can afford some heat in my conservatory for a greater range of plants. Aheibi, i am not good at technology, but I can see a better and cheaper way of growing a WIDER variety of plants than you are used to. Leds last for 20yrs or more depending on make. whilst your traditional flourescent types may keep going, how do you know when they have lost strength, as they do. but as they haven;t yet packed up, you spend more and more on nutrients that the plants cannot take up, with the result that your yields are lower, with less potency.

Most of us aregrowing a variety of plants with much less specific needs. Foil works fine, and probably better with leds. I would love to know why you want to recommend such an energy wasteful way of growing. tto much heat? venting? Such specific bulbs. Get a Life. Plants are far more adaptable than you are, and would prefer a little less light (recoverable), than possible scorching (Fried, dead plants)

I believe that as we all become more accustomed to LED light, we will find many more ways to mix it and use it. What one person finds clear light may be uncomfortable to another. But we can buy pure colours to customize our light. Gardeners need a different light to Chefs, they need a different light to Tailors, I use a completely different light to sew than I do to read, and a different mix to do my job as a dog groomer. Wehave never had such versaltility in lighting. It should be thoroughly embraced. It is clean, clear, cheap to run, customisible, cool in use, long-lasting, and so, must be the most Eco-friendly lighting option available. Although I am sure someone will disabuse me of that fact!

Technoaussie™ (author)2015-02-17

I have always been concerned with the taste of hydroponic vegetables. The HP lettuce we get in Brisbane Australia grown this way doesn't even taste like lettuce. How is the taste of your stuff? I've got room for a box like yours in my kitchen I'd love to try it but the fear of disappointment in flavour over the outdoor patch we have has always stopped me.

tgvoss (author)Technoaussie™2015-02-18

I have been doing different variations on hydroponics for a few years now. I have not noticed a taste difference. I think the fertilizer and lighting is key. Try using a high quality fertilizer that you can trust. Is there an indoor growing store that supplies different kinds? Talk to the sales rep to see what they recommend for lettuce. I have also chosen to grow in sterilized "potting soil". This more closely mimics what plants are used to growing in, I am not sure if it is better for the taste but I do like to know they are in an organic decomposed earth substrate.

Jim Myers (author)2015-02-18

It looks like you used 21 LED rows for your project. Is this correct?

tgvoss (author)Jim Myers2015-02-18

I ended up with 23 rows, it all depends on the size of your cookie sheet and the size of your box you are looking to have plants in.

eclectic99 (author)2015-02-17

Thanks for the link for the white light strips. I too have been using red/blue LEDs on a plant that was bred for cool white. I will try your combos to see if this works better.

BTW, the www is so full of hype and misleading reflectivity data for aluminized mylar, aluminum foil, and white paint that i chose reflective mylar as possibly easier to use with the 3M 77 spray.

jmacdonald13 (author)2015-02-17

Found them on the UK eBay site. Thank you looks good and sparks ideas. :-)

Elac. (author)2015-02-15
Great instructable, your basil and lettuce look happy in their home.

LED lighting is the way to go.

A few grow box tips:

Using flat white paint on the walls give a more even reflection of light then aluminum does.

*These 7020 LED hard aluminum strips provide an increase in lumen and the aluminum strip acts as a heatsink.

Using a 2:1 ratio of cool white to warm white strips will give a better spectrum of light for increased foliage growth.

a 2:1 ratio of warm white to cool white strips will give a better
spectrum of light for fuller flower production and heavier fruit yields.

For lettuce and basil a 2:1 ratio of cool white to warm white is best.

*My link to the 7020 strips doesn't seem to be working so here is the address:

tgvoss (author)Elac.2015-02-15

Awesome, love those strips. And I had considered using a mix on my next attempt. The light I am using right now I also use for videography but that might be a nice feature as well, being able to tune in the right color temperature balance with the two on a voltage regulator.

jayludden (author)2015-02-15

Awesome 'ible. Question: Is cardboard a fire hazard? I've used foil covered milk crates before, which work great. I have way more access to cardboard boxes than milk crates, but I was worried it might be a safety hazard. Thanks!

tgvoss (author)jayludden2015-02-15

The heat generated by these led's is minuscule when they are placed on top. I would not do a cardboard box with a CFL or the likes.

tomarrow (author)2015-02-12

don't fertilize young seedlings

tgvoss (author)tomarrow2015-02-13

Yes, that is an assumption. Most start a fertilizing schedule after transplanting to a larger pot.

Kafukai (author)2015-02-13

LED is an energy saving bulb, it's difficult to use and eventually you would use much more, not very effeicnt for growing plants.

You should use the old school system of HPS light or MH light or combination of both, but you should take in consider the bulbs aren't cheap and either the energy. Also you have to vent it, it uses a lot of heat. But the pros are that you can grow anything anywhere.

tomatoskins (author)2015-02-12

I would have never thought to use LEDs for grow lights. I've always just used flourecent lights. Have you tried both and do you notice a difference?

tgvoss (author)tomatoskins2015-02-12

I used to use CFL and T12 tubes to do this but was always disappointed by the amount of lights you would need to grow sufficiently fast. This setup has more light in a tighter space for less cost.

I will see in a few months if the growth is sufficient with the amount of lights I used (~20M of strip lights).

tomatoskins (author)tgvoss2015-02-12

I think I know what to switch to when it's time to start planting!

About This Instructable




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