Introduction: Automated Low Watt LED Mini Greenhouse

By hyperlocavore.com
About: hyperlocavore.com is a yardsharing community. we built it to encourage people to change their lawns to verdant food producing paradises, with their neighbors, friends, family and faith communities. We envision…
In this instructable you will learn how to build a mini green house, with timed grow lights.

Step 1: Materials List

You may not want or need as much insulation as I used. Its very cold where I live. It is not a thing of beauty and was build strictly to function as a place to start plants and extend our very short growing season. It hides in our garage.

So far it has been a constant 58 degrees inside the greenhouse. I have started only cold friendly plants. It likely gets a bit chillier when the lights go off.

Materials:

Many times you can find some of what you need for free on freecyle.org, reyooz.com, thinggo.com or trusty craigslist.org. A thrift store is another good place to check for some of these items.

Shelf with 5 shelves $50.00
8 LED grow light panels $240.00
Roll of sheet plastic $12.00
2 Power strips $10.00
2 Timers $14.00
1 Thermometer $ 2.50
Trays $3.00

Total: About 331.50 (plus tax)

Time of useful life. The only element I expect not to last for at least 10 years are the LED panels.

Things I had on hand:

old blanket
cotton cord
zip ties
staple gun
blinder clips
bubble wrap
duct tape
some lattice panel to
keep the barn cats out

Notes:

  • LEDWholesalers on ebay.com  2 orders - 900 LED Grow light 4 Red + Blue Hydroponic Lamp Panels. They have a few negative comments but for the most part they get 5 stars.
  • My shelf was a bargain apparently. I cant find these very cheap online.
  • Make sure the timers are the grounded type (three prong.)
  • The power strips plug into the timers.
  • The LED panels go into the power strips.

Step 2: Build Shelf

Assemble shelf per directions that come with shelf.

Step 3: Test LED Panels

Test all of your panels. Plug them in and inspect them for flaws. You may need to send them back and its easier to do when they are not attached.

Step 4: Tie LED Panels to the Undersides of the Shelves

Attach 2 LED panels to undersides of each shelf. I used cotton cord and staples because it will be easy to remove panels if they go bad. Cut the cotton cord about 3.5 feet long, double fold in half. Use staple gun to staple doubled cord to underside of the shelf. Do this twice for each panel. Make sure there is enough room to slide the panel in between the cotton cord.

Step 5: Attach Powerstrips to Shelves

Use zip ties to attach power strips to the back braces of the shelf.

Step 6: Set Timers

Set timers for the amount of daylight you want. Follow instructions on your timer. People differ on this. I have mine set for 14 hours. We will see how this goes.

Step 7: Plug LED Panels Into Power Strips

Plug all panels into the two strips. Test the strips and make sure everything is working.

Step 8: Plug Power Strips

Plug power strips into timers and plug timers into grounded outlet.

Step 9: Covering the Shelf

Staple the bubble wrap panels from the top shelf. Length of bubble wrap should be a little longer than the height of your shelf. Use 4-6 panels to surround three sides and some of the front of the shelf system.

Use duct tap to close gaps between bubble wrap panels.

Double the bubblewrap if you want more insulation.

Do not seal the thing up tightly. You want some air in there. Stay away from PVC plastics.

Step 10: Use Sheet Plastic for Outer Walls

Make plastic sheets into panels that will cover three sides + of the shelf.
Wrap about 8 inches of the plastic sheeting from the side to the front.
Staple the long sheets of plastic also from the top of the shelf. Note: I used the plastic folded over triple layered.
Use duct tape to close gaps in plastic sheet panels.
Do not try to 'seal' the thing up. You want air flow.
Stay away from PVC based plastics. They may offgas.

Step 11: Make a Door

Create 4th panel  door. Cut plastic the height plus 4 inches of shelf. Use a layer or three of bubble wrap. Layer the plastic and the bubble wrap like a giant sandwich. Duct tape edges if you like. Staple the door to the outside of the top shelf (as you have with the other panels)

Use the binder clip to hold the door to the side when you want access to the shelves.

Step 12: Insulate

Cover top with blanket for insulation if you live in a cold place.

Step 13: Attach Thermometer

Use cotton cord to attach the thermometer to some where inside the shelf, in a place that is easily visible to you.

Step 14: Fill With Trays and Seedlings

The rest is up to you!

You might want to use shoe boxes or bricks to allow you to get the seedlings closer to the lights when they are younger.

So far we have seen a regular temperature of 58 degrees F, inside the enclosure. Pretty good considering it's 30 degrees most days!