Introduction: DIY- Indoor Seedling Grow Box

About: I just like to make stuff.

I like to grow my own Herbs and veggies but in Mich its kinda hard to do in the winter, Plants don't care for the cold by the window and I kill more that way, So I wanted to see if we could Turn a old & really cheap junk tool chest into a energy efficient Seedling grow box for under $10.00

And spring is just around the corner and allot of us are getting our prep work underway. I found this old junk tool chest and whipped into a nice little seedling starter & transplant grow box, It uses 55watt CFL florescent vegetation light, However you can put any light configuration or LED grow lights you feel is right for you into this small tool chest / Grow box.

I just used what I had laying around, As time's are super tight with money for allot of folks. (me included)
If you have to buy the parts I am 99% positive it will not cost more then Ten dollars. It tooks about 3 Hrs from design to completed. Painting took another day. (optional)

There is little to no heat generated by the CLF. The chest works as a great Heat sink and when fans are running the box stays even cooler. As this build has a AC power cord on it you can use a timer with it. And or step one up on me and put self watering system in as well!

Warning AC current can KILL you!!! If you have no knowledge of basic electricity and 120 volt systems and want to build this find someone who does know! Never work with live wires or devices make sure power is off! This build requires the use of tools that can hurt you be sure to use eye and hand protection!

Step 1: Tools and Parts


Metal File
Tin Snips
Flat Head Screw Driver
Tape measure
Soldering Iron, Flux, Solder
Hot glue gun 
Small Punch or Screw Driver
Razor knife
Wire Strippers 
Wire cutters
Sharpie or Pencil
Drill & Drill bits 
Multi meter


3 Computer case fans.
3 Case fan guards.
1 Grounded Outlet 120 v.
1 Single pole toggle Switch 120v.
1 Double gang Handy Box or like me use a couple of plastic boxes to make a double. (Handy Box's are metal)
1 12v DC power supply.
1 Single pole toggle switch for low voltage. (can get from auto stores)
Tin foil or Mylar.
12 Case fan screws or 12  8/32 x 2  screws washers & nuts.
1 Power cord.
1 Lamp Fixture Socket. 
 Veg light or lights of your choosing.
 4 to 5  feet of low voltage wire. (like old telephone wire)
 Sand paper & primer & paint if you choose to paint.

Step 2: Prep the Box

1. The door has to come off, So grab the Flat head screw driver & hammer and tap out the door pin's and remove the door. Set aside Door as there is a little more work to be done to it later.

2. Next to come off are the Casters. Again we use the mighty Hammer to tap the caster out of there guide holes. Keep em for other projects.

3. Remove the hasp lock by tapping the retaining pin out with a small punch or screwdriver.

4. clean it up and it's ready.

Step 3: Cutting the Holes for Switch Fans & Light

1. The Light: 
 Flip the chest on it's side (pick the side you want to be top) Find the center of the area and back it up 3 inch's from the backside of the chest so the the light is off center by a few inch's, Mark it X marks the spot, Use the compass to mark out your hole for the Light.

2. Use a Large Drill bit you need the hole to be big enough for the Tin Snips to fit in easily. Drill through don't worry about burrs.

3.  Now the hole is cut use the Metal File to clean off the burrs. 

4. Repeat this step for cutting in the 3 fans.  ( Holes for fan are not the same size as light)

5. Cut in 2 holes on each side for fans and 1 more on the top by a corner. Be sure to center you fans on the side and top to provide a good air flow. I have 2 intakes and 1 exhaust on this box. 

6. Once the hole for the Light & Fans are cut in, Use a Fan & drill to mark the holes for the mounting screws (Don't try to drill the holes with the fan). Repeat this step for all 3 fans.

7. Keep your Switch close to the corner where the power will be connected. Drill the hole size appropriate for your Switch.

Step 4: Lining the Inside Box With Tin Foil or Mylar

1. Pretty simple task at this step. Grab your Tin Foil or Mylar and start to line The inside Top, Sides and the Back. I had no Mylar and went with what was available Tin foil.  For a quick and easy way to stick the Foil is using some kind of silicone I used some automotive RTV Blue and put little dots on the Dull side of the Tin Foil. Just cover over the fan & light holes.

2. Use a Drill bit or sharp pencil to poke a hole through the center of the foil for the Light and fans.

3. Using a sharp razor knife slice the foil like a pizza then fold back.

Step 5: Installing the Fans, Switch & Wiring the 12 Volt System

1. Peel off the Foil star. 

2. Mount the fan & fan guard.

3. Mount the Switch.

4. Insert the power supply cable though the side in a hole I did not get a pic of next to where the handy box will be mounted. Put a dab of hot glue or silicone in the hole to secure the wire.

5. Run the wires hot glue them into place. Make sure the wires are ran on the top side so to avoid water damage.

6. connecting the wires: The 2 Fans & traveler (That's 3 conductors) get connected straight forward Red to Red  Black to Black.

7. Connect all Red wires from the Fans +12 volts to one side of the Switch.

8. Connect The power in from the PSU to other side of the Switch.

9. Connect all Black wires to the ground of the PSU. 

10. Hot glue the bundle of wires to foil in corner out of the way.

The 12 volt system is done.

Step 6: Installing the Bulb

The Bulb:

I wanted to use a light bar on the inside of this project but all I had was this 55 watt veg light. 

1. The hole is a snug fit so gently twist the light into the hole till the base is half way out.

2. Run a bead of Silicone or some RTV Blue like I did to seal any gaps for light to escape.

Step 7: Installing the 120 Volt Wiring

Quick parts check:

1. Grounded power cord.

2. Grounded outlet.

3. Single pole toggle switch.

4. Light socket.


1. Cut off the female end of the power cord.

2. Strip the wire into 3 conductors, Making sure you identify  the common wire.  

3. Depending on what kind of box you are using it's is pretty straight forward. Place your double gang box or boxes like mine, Mark them out. Drill a couple of holes to mount the boxes to the chest. Make sure that you bond the ground from power cord to the chest  by means of the screws used to fasten the box to the chest. another photo I missed ... (And the correct box to use would be a Handy box with Romex connectors)

4. Use the Flat head screw driver to pop out 2 knock outs on the back of the box. Insert the power cord into the back of the box.
Insert the power cord from the light fixture. ( To keep the polarity correct you must identify the common wire on the light fixture, power cord and jumper)  

5. Connect the common & Ground wires to common side of the outlet, Cut away excess wire. (you must put the wires on the screw clockwise on all screws, Or they will unwind off the screw) 

6. Connect the power wire to the power side of the outlet.  The power cord connection is now complete.

7. Connect the power wire from the Light Fixture to the power on side of the Switch.

8. Here we need a small jumper wire about a foot long will do, Identify a common wire. (Gives some to play with)

9. Wire the jumper to the outlet making sure you put the common on the common screw, And the power on the power screw. ( outlets have 5 screws, 2 white screws and 2 copper colored screws, And one green screw, white is common, copper is power, Green is ground)

10. Tape up the outlet with electrical black tape and it is wired.

11. Connect the hot wire from the jumper to the off side of the switch. Connect the Power wire from the light socket to the on side of the switch. Tape the Switch with electrical Black tape and it is wired.

12. Yellow wire nut the commons from the jumper & light fixture.

The 120 volt AC connections are complete Install the devices to the box.

Step 8: The Door

I didn't want to keep this little peg board on so off it went. This is optional.

1. Hammer & Chisel the sheet off, There were only six weld points so it came off very easy.

2. Sand off the rust if any, There was no paint under this so expect some rust. clean up & paint.

3. When the paint is dry insert the door pins back in. I have a eye hook to hold the door open. 

4. Puts some veggies or herb seedlings and watch em grow!

If you made it this far into the instructable and you like what you see and please leave some feedback & rate this instructable. 
Happy Gardening! 

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