Do you love growing plants, but hate remembering to water them?

Do you have very little space in your tiny, exorbitantly-priced apartment?

Do your friends consume a worrying amount of plastic bottles?

If you answered yes to one or more of these questions, consider this hydroponics system. Or not, it doesn’t matter; we’ll all die soon anyway.

How I Designed This

Why?

I really enjoy having plants in my living space. However, I’m terrible at remembering to water my plants. And even when I do manage to remember, it’s a huge hassle to get it done. I have to bring them over to the sink and soak them, then allow them to fully drain. I have about 15 plants, so it takes a while.

In my efforts to solve this problem, I found hydroponics: growing plants without soil. I found a few systems online, but they didn’t fit my needs well enough. They didn’t make the most of available space, were not expandable, not aesthetically pleasing, and somehow, they were still very expensive. I felt I could design something more suitable.

Design Requirements

The system should:
1) be built with only my 3d printer and drill: no saws or other power tools. I don’t have a shop and wanted the build to be easily reproducible.
2) use recycled materials as much as possible.
3) should be as aesthetically pleasing and unobtrusive as possible, since it’ll be inside my home

Due to my limited space, I decided on a vertical system rather than horizontal. The big factor here was saving space. I have plenty of vertical space, but not much horizontal space in my small apartment.

I researched the different types of hydro systems and found one that’s very popular with vertical farmers: Nutrient Film Technique. It flows water over the plants at fixed intervals. The plants have a breathing period of several hours before the water is pumped through again.

Design Decisions

Once I had chosen a system, I dug through online listings for NFT systems. After quadruple-checking none of the available systems met my needs, I did a quick search on thingiverse. Turns out, someone else had a similar train of thought, and designed 3DPonics. It’s awesome: it’s composed of re-used 2L bottles hung vertically. Apparently, it’s going to be used in space. Neat.

Due to the open-source nature of the project, I was able to take my favorite parts of that system:

1) the re-use of 2L bottles
2) the vertical design

…and add my own enhancements.
Modularize each node, so it can be added and removed easily.
Make the support structure the wall itself, rather than a post or its parent node.

First, I modified the existing 2L bottle holder to use less material. Then, I designed a sliding mechanism by which each node can be easily mounted to the wall. I cannot for the life of me figure out what the name of this should be. I’m sure it exists already, but googling “sliding mount connection” didn’t get me anything. So if you know, let me know.

First Build Lessons

I built the topmost node first, so I wouldn’t have to move the hose around when I decided to add more nodes. It was definitely a good idea to do one first, then add more nodes as I learned about the system. I was able to save more material in the bottle holder by moving it further down the bottle, firm up the connection between the mount, holder, and wall, and added a little more tolerance between the mount and bottle holder for easier removal.

Issues & Solutions

In building my first node, I found out my existing water pump wouldn’t pump the water high enough, so I got a new one. I’m saving the old one for my next build; it’ll be a lower-height version, with maybe 3 nodes instead of 4.

I also ran into an issue with the drip cap that attached to the bottle cap area. It was built for ¾ inch tubes and I was using ¼ inch tubing. Luckily, I found exactly what I needed on thingiverse. It was originally a design for bleeding brake fluid, but it found new life in this project. Awesome.

Also, the bottom node needs to be able to withstand a lot of water pressure. The drip cap keeps springing leaks, no matter how much super glue I layered onto it. I made a quick band-aid fix with saran wrap. A better solution is to use marine-grade epoxy when attaching the drip cap to the bottle.

The bottom node got plugged with one of the clay pellets, and nearly overflowed before I caught it. I added a metal screen to prevent that from happening again.

To shield my guests’ eyes from the blinding LED grow lights, I ordered a piece of aluminum from Home Depot. I painted it white on the outside and mounted it vertically in front of the LED strip. I would have used particle board, but it only came in 8ft lengths, so I’d have to cut it in half, which would have violated my no-power-tools constraint. It’s a blessing in disguise: the metal will reflect more light back into the system.

Future Work

Good areas for future expansion include:

Automatic monitoring of PH levels of the water
Automatic nutrient mixing and monitoring
Individual light strips in a ring around each plant
Adding fish to the water tank (aquaponics)

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