How to Make a Lightbulb Greenhouse

I’ve had this project on my list for years. As a fan of DIY hacks, any sort of repurposed/reused doodads, AND gardening, how could I resist something as cool as a light bulb greenhouse?

Any plants that you grow inside it will reuse the water supply, which is helpful if you forget to water your plants or go on vacation. Personally, I just built it because it looks cool.

I got the original instructions from my Best of Instructables book and used that as a general guide, making a few small changes. You can tweak yours too and make it look however you like.

Light Bulb Greenhouse

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Step 1: Gather Materials

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You will need:

  • a used lightbulb — the old-school kind, not those new energy-saving bulbs
  • a small piece of rubber — I used a worn inner tube from my bike
  • a shower flange or anything with a wide base that gradually narrows at the top — I used a metal thing (??) that I scrounged from a pile of random stuff in the basement.
  • a lamp socket — I bought this at the hardware store for about $5.
  • pliers, sharp knife, wire cutters, screwdriver
  • sandpaper
  • gloves, safety glasses (optional, but smart: you’ll be pulling apart bits of glass and metal)
  • strong glue. I used a craft glue gun.

Step 2: Prepare the Lightbulb

Put on your gloves and safety glasses. There’s a small metal bit on the bottom of the bulb: Pull that off with the pliers. Next, use a long, sharp object (I used chopsticks and a steak knife) to bust the electrical bits. Pieces of glass and metal will pop out, so be careful. You want to clear out the bottom of the bulb to make an opening. Optional step: use sandpaper or a file to smooth the metal edges.

Remove the white paint from the inside using hot water and soap. I stuck a chopstick in there to scrape some of it off, but it would probably be easier to use one of those mini brushes on a stick that you can buy for washing dishes.

Step 3: Disassemble the Lamp Socket

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Keep in mind that I used the cheapest lamp socket I could find: if you’re using a high-quality part, it might be built differently.

You’ll need to pull apart the lamp socket to get to Part 1 (part that the bulb screws into). Part 1, 3, and 4 are attached together as a unit. Pull this unit out of Part 2  (the long metal sleeve). It comes right out. Set Part 2 aside. You’ll be using it later.

Remove Part 3 first. It’s attached with little screws, so just use the screwdriver to remove them and pull the unit apart. Easy peasy.

Now all you need to do is detach Part 1 from Part 4 (the little black part). They’re held together with two metal bits that resemble screws, except you can’t unscrew them. There’s a crack between the parts; you’ll want to widen it so you can get the wire cutters into it. I used a knife to help pry the pieces apart, then used a bit of elbow grease to pull them apart with my hands. Once the crack is wide enough, you can snip the two metal bits with wire cutters. Part 1 is now completely detached. Ta-da!

Step 4: Glue Time!!

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This is the easiest step. Take Part 1 and line it up with the base so it covers the opening. Glue it. Cut a small strip of rubber and glue it, wrapping it around Part 1. This is the seal, so make sure it covers any little cracks between the base and the socket.

Step 5: Prepare the Metal Sleeve

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Depending on the parts you’re using, you may be able to skip this step. Basically, we want the metal sleeve (Part 2) to cover the lamp socket and rubber strip. We also want the lightbulb to fit inside the sleeve from the top and screw into the socket (see photo in Step 5).

The metal sleeve might be too long, so test your project to see if the parts fit together properly. If they do, go directly to Step 5. If the bulb doesn’t reach the socket, you can follow this step (recommended) or skip it (the greenhouse will still work,  but it won’t look as nice).

The metal sleeve was too long for me to properly fit the bulb into the socket, so I cut it to fit. I measured it against the base and socket to see where I needed to cut it and marked the inside with a sharpie.

Next, I broke off the pieces. You can use wire cutters here if you want clean lines, but the metal is weak enough to bend and snap off with pliers. Once you’ve cut it to the length you need, use the sandpaper or file to smooth out the sharp edges.

Step 5: Put It All Together!

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Slip the metal sleeve over the socket, then screw in the lightbulb. It’s finished!

To use it, plant seeds in a pot of dirt and put the lightbulb greenhouse on top. Put it on a windowsill or somewhere sunny. The seedlings will eventually grow into the bulb.

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And that’s it! I can finally cross that project off my list. I’ll make sure to update this post once I’ve got something growing inside the lightbulb greenhouse.

Questions or comments? Post them in the comment section below!

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