I’ve been using DIY versions of a self-watering container with a name similar to “Dirt Box” (or “dearth box”) as well as upside-down tomato planters for the past couple years on my concrete, second-story balcony. Here’s how I took the basic wicking water principles of a popular patented and trademarked earth-filled box, and applied it to my upside-down hanging tomatoes.
Upside-down planters are cool. The major weak point has always been keeping the plants hydrated, especially during the peak of summer while producing fruit. In the first year, with no special consideration for watering, my plants suffered due to my unwillingness to schlep water to the porch and lift it all the way to the top of each planter. I mean every day?!?! Come on. It was never going to happen.
Last year, I tried drip irrigation. I suspended a tank of water above the level of the top of the upside-down planters and ran a thin hose across the tops of the planters with drip nozzles. The problem was that I could never get the water balanced so the first planter would get the same amount of water as the last. I also had problems getting them to drip slowly enough to last all day. Most of the time, I would be able to keep them hydrated but there was a lot of waste as the the water would run through the plants after an hour or less. Going away for the weekend meant severe drought damage.
I made my own planters in the style of the planters named after a popular planet and marketed by a company with at least one trademark attorney, and that was the best thing to happen to my balcony. I could be relaxed about watering and my vegetable plants thrive. This year, I finally figured out how to give the hanging tomato planters a reservoir without adding weight to the planters and losing dirt volume. After setting up this system, 100% of the water is going into the plants. There is absolutely no run-off waste.
Step 1: Overview
My system has four planters and one reservoir. There is a hose from the reservoir that runs horizontally under the planters. Each planter has a hose at the bottom which is fat enough to contain wick. This hose is connected to the horizontal hose. The wick is about 10 inches long with half of it in the hose and half inside the planter. I made the reservoir out of a 4′ long section of 4″ diameter PVC pipe. The reservoir should be hung so the lowest point of the reservoir is just barely higher than the lowest point of the wicks. The reservoir should also be shallow enough that the water at its highest level is below the dirt. The water travels freely from the reservoir down the hose and back up into each wick. The wick, using the power of capillary action, takes the water up into the dirt where the plant roots have a party. If you understand this concept, you’re 80% done.
My setup is only one example of how this can work. You can use this as a guideline to make 1,000 planters with 20 reservoirs. Go according to the materials you can acquire and what physics will let you get away with. While planning, always be mindful of how much your planters and reservoir will weigh when they are full, how strong the chains are, and the connections that hold them in place. My assumption is that you can figure out how to hang these large, awkward items in a safe way. I will show you how to build the parts for water and dirt.