a couple of summers I recently started having a problem with the plants on my roof deck. Specifically, I didn’t have a reliable way to water my herb garden for an extended period of time. Yes, I could ask my neighbors to do it from time to time, but I go a lot and I didn’t want to spend all my goodwill credit in one place.
My setup also posed problems. It’s a pot, trough and planter garden, known as a container garden, that follows the periphery of my 10-by-17-foot deck. A sprinkler with a timer wouldn’t work, because I didn’t want to soak my entire deck and waste water, and watering spikes or globes wouldn’t last long enough. Additionally, I had a variety of pot and planter sizes, ranging from four 20-liter galvanized tubs to a pair of 100-gallon waterers, along with a 1-cubic-foot ceramic pot that insulates my mint and a mini waterer for my sage.
All in all it’s a nice little setup, but everyone has different watering needs. Talking to people at garden centers confirmed that there weren’t many options for the type of automated watering I wanted to do.
drop drip
After a ridiculous amount of research, I zeroed in on a solution. An Austrian company called Blumat has a system that uses a spike-shaped sensor (more colloquially called a “carrot”) that has a ceramic cone beneath a sealed water chamber. It’s all covered with a diaphragm that’s connected to a small valve on top, making it a sleek, sealed, self-contained valve that controls flow through a 3-millimeter drip tube. When the soil around the cone dries, osmosis through the ceramic lowers a diaphragm at the top, gradually opening the valve and allowing water to flow through the tube. When the soil is wet, the diaphragm rises and the valve closes.
Photography: Tropf Blumat
There are many specialist kits and parts from Blumat, and finding out exactly what I needed was daunting, so I called Sustainable Village, Blumat distributor in Colorado, looking for help. It’s possible to improvise, but you’ll probably benefit from doing the same.
This meant that I needed several different parts of what they call Tropf-Blumat system (“tropf” means “drip” in German), including sensors; things called “drip tape,” which is like a soaker hose; and small strings of “drippers” that connect to the sensor and distribute water around medium-sized pots. There was also a “flow reducer” that connects to the faucet and regulates the pressure, a pencil-thick rubber feed tube, and a roll of 3-millimeter drip tubing that connected the feed line to the sensor in each pot.
Blumat’s site recommends the Tropf configuration for “plants on balconies, patios, greenhouses and raised beds.” The representative guided me to a couple of kits and a couple of individual items.
Photography: Tropf Blumat
Some assembly required
When it all arrived, there were enough details that it reminded me of an adult Lego game, complicated enough that I cleaned my dining room table and chairs, made cardboard cutouts of my pots and feeders, and laid out all my new supplies. This was extra work, but it allowed me to stay organized, since each installation is essentially custom. My 20 liter tubs and sage waterer would each have a sensor to control the flow to a series of drippers to distribute the water evenly. Each of the hundred-gallon waterers had an extra-large sensor that controlled flow to the drip tape that zigzagged across the soil surface.
After a couple of hours of installation, I turned on the faucet and held my breath. Some of the drippers started dripping very slowly and some didn’t. For a while nothing visible happened in the large feeders, as it took a while for the drip tape to start sweating water droplets. It soon became clear that by having one sensor per container, the flow of each one could be customized. A plant that was very thirsty or bathed in the sun received more water, while a succulent that drank slowly in the shade received less. Over the next few days, I checked the soil in each pot and used the valve on the top of each sensor to adjust the flow.