Small Indoor LED Plant Grow Room





Introduction: 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


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


  • Box Cutter
  • Scissors

Step 2: 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

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

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.



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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.

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.

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.

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.


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.

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.

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.

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.

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).


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.