Greenwall Part 4: CoTS

    Part 1 was where I really didn't know what I even wanted. Something big and green ... Part 2 was where I decided to go big but still didn't really know what I was doing. Confident I could do it but not sure how long it was going to take. In Part 3 I showed how clever I was by designing and building from scratch my own automated watering system. Hooray for me. I always think of unnecessarily complicated robotic solutions first. It worked perfectly for a few months, but I didn't use fully sealed bearings and eventually the bearings rusted and seized. On top of that it was always noisy and sprayed water everywhere because it used a 3d printed seal. So I threw that out and just bought 13 CoTS solenoids valves. They cost $5/each. I printed a frame to hold them all together and the entire watering system just got so much simpler and more reliable. Whenever they wear out, I have a box full of spares because they only cost $5. This also let me simplify the control code quite a bit.

    I also replaced the tupperware container I was using as a water reservoir with a custom-built tank. I just screwed together some plywood into a box and dropped in a plastic liner. Then I made a cover out of PVC panels so water can drip down along the full length of the wall directly into the reservoir. The old tupperware container held two or three gallons, which was fine when I had twenty plants. With 200 plants, that wouldn't be enough to water the wall once. The new tank holds ~13 gallons and only needs to be refilled about once a month. Then I made a plastic cover for the tank out of PVC boards and my wonderful girlfriend Julie painted a mural on it.

    A few other things I've learned over the past few months include

  • Most plants are happier when they get watered multiple times per day, instead of once per day. Especially ferns. The felt pockets don't retain much water and the soil I've used, with lots of redwood bark and sphagnum moss to make it lightweight, also doesn't retain much water.
  • Plants absorb a lot of runoff from the plants above (I assumed most of it would just run down the back wall) and this means I can't plant low-water plants like ZZs on the bottom half of the wall because they'll die of root rot. It's also difficult to keep ferns happy on the top rows because all their water immediately drips away.
  • Some of my plants are propagating really nicely and some I haven't been able to propagate at all. Oddly, my pothoses won't propagate at all. They won't form new branches, no matter what I do.
  • Originally I was imaging having many dozens of different kinds of plants, maybe a few of each, but I have two hundred pockets to fill so I'm going to settle on the 20 varieties I already have and I'll be propagating those to fill the space. I might find one or two new plants to fill the top quarter.

    That's where I am today. The lighting system was easy to build and I haven't thought about it since I installed it over a year ago. The watering system is finally fully automated and very reliable. And knowing that, I'm finally ready to fill up the whole wall. I didn't want to plant 200 plants and then have the watering system break down on me. It'll take a while more to fill the wall completely, but I'm pretty happy with where it is today. I want a green rainbow. Green everywhere, no flowers, no reds or yellows, but a hundred different textures. I just added in some asparagus ferns, maiden hair ferns, fluffy ruffle ferns, ivy, and some weird looking little plant that I can't remember the name of but it looks really cool. Another one or two additions like that and the wall will be complete. Things I want to improve include finding a quieter pump and looking for a clean way to mist the ferns that doesn't protrude significantly from the wall and doesn't get water all over the floor.

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