Food Jammers DIY basement farm: Grow Tubes for Subtle Technologies

June 1, 2010
By Sketch Editors

Production of micro greens and sprouts uses little ebergy

Going vertical turns any window or wall into a farm

There has been a lot of excitement around urban agriculture and indoor farming in Toronto, but not so many examples to look to;  I wanted to try growing food in a movie theatre with no natural light.

We grew food in Innis Town Hall theatre where Subtle Technologies takes place and Nobu and I presented. The goal is to have as few inputs and use as little energy as possible.  The design takes little space and is suited to hanging in a window where the LED’s act only as a light supplement.

Vermicomposting and new developments in lighting make it possible to grow food year-round for cents a day.  Here are some of the basics on growing your own food indoors.

I’ve been successfully growing food in a basement for a couple years, since having my mind blown at Growing Power in Milwaukee.  I don’t have a greenhouse or a sunny yard but do have a basement so I wondered if there was a way to use low wattage artificial light to grow food.  The idea is simple and low tech.  Plants are amazing; all you have to do is set up some simple conditions for them to germinate and grow a few weeks.  Leafy greens and sprouts don’t need tons of wattage like fruiting plants.  These plants, like arugula, sunflower, mustard, wheat grass, and chard initially grow in the dark and green up under a couple of hardware store shop lights, 32 watts each. The experiment will be to see if LED’s do the trick.

Produce your own nutrients by vermicomposting: some organic waste from the kitchen, dead leaves from the yard, and wood shavings from the shop  turn into a black, nutrient rich growing medium.  The key is to keep the moisture and nitrogen-carbon balance in check to have no smell and happy worms.  I keep it to veggie and fruit scraps, coffee grounds, leaves, and saw dust (no ply or mdf).   There’s tons of info on the web, but rule of thumb is 30% nitrogen (live plants, scraps, green things) to 70% carbon (dried leaves, wood shavings, paper, brown things).  Sort the worms from the compost by using the Will Allen method of window screen with food on top– the worms pass through when the food below is exhausted and you lift the layer to a new bin.   Or expose the bin to light, sending the worms down, and harvest the top layer of worm-free castings.  Hardware cloth in the bottom of a box makes a sifter, the last step to having worm castings ready to use.

The only input I buy is coir, a coconut husk waste product that acts as a moisture sink.  Use it instead of peat, which takes a couple hundred years to from in bogs.   Mix the worm castings and coir one part castings to two coir.  You can use less castings for sprouts since most of the nutrients used by the sprout are in the seed.  Longer growth plants like arugula benefit from the nutrients.  I re-compost everything so it’s easier for me to have one formula.

Cafeteria trays are deep enough for sprouting, and clay window box drip trays work well.  Hanging pots, or any container for growing will do.  After putting the mix in the tray/tube, sprout the seeds in jars.  Fill a mason jar one-third full with sunflower, pea, or other seeds and soak overnight.  They expand so leave room.  Cover with screen, panty hose, or a tea strainer.  Arugula and other fine, mucilaginous seeds you add directly to the medium in the tray.   Drain and mix into the first inch of grow medium and lightly water.  You can sow on top and cover the first 2 days but I sometimes get mold that way so I prefer letting the coir regulate the moisture.  Put your lights on a timer, run 12 to 16 hours a day (I cycle them at night when electricity is half price), with a fan if you want to help strengthen the plants for transplant (or keep mold at bay).   In a week to 2 weeks you have a crop, watering every other day or as needed.

Next level is to go ultra compact with the grow tubes.

I used HDPE 6 inch water main pipe, CSA’d potable for water.  I chose HDPE, though harder to locate than vinyl pipe, because it’s softer to work with and vinyl pipe is an environmental nightmare, and smells noxious when you cut it.

As a demo, this project is just a sketch of the possibilities in window-LED assisted food growth.  The prototype is HDPE pipe, but the end goal is to extrude a clay profile after finding the right dimensions and go post-plastic.

There is no substitute or simulation for natural light, wind, rain, and soil.  This is an exercise in growing indoors and this plastic beast is a first step.

Next I cut holes with a drill press and 5 inch hole saw.  I found front load (HE) hippy laundry liquid to be a good cutting fluid diluted in water as it keeps the plastic from melting and binding and doesn’t sud.

I put a hole at either end, then two more 2 inches apart in the middle, keeping a bridge in the centre in order to keep th e tube from collapsing.   The next Step is to join each pair of holes with a jigsaw set to slowest speed. Last step is to cle an edges with a half-round file and sand paper.  Eye-bolts and hardware connect one tube to the aircraft cable and I-beam clamps make the unit attach to an I-beam or piece of angle iron mounted to a wall or lintel.  Each tube can be removed for harvesting.


The tubes were installed to either s ide of the stage in the Theatre for the duration of the conference.

he 5050 S MD leds specs are as follows:

5-7 l umens per LED

beam angle is 120 degrees

these constant vo ltage with an input of 12vDC

Current consumption per meter is 0.5A/meter (at 12 volts that’s 6 watts a meter)

colour is 6500K

the fixtures are IP68

The LED’s were intense enough to produce quite a bit of food.  I weighed the produce from the tubes and just one 6×48 inch tube produced .375 kg or almost a pound of sunflower sprouts. In 10 days the 8 tubes produced 1.375 kg or 3 pounds of food, and that doesn’t take into account the pea shoots as they were still coming into maturity.  The tubes yielded another 250g or half pound of pea shoots 4 days later, making the total 1.575 Kg or 3 and a half pounds. In a movie theater.  The tubes should work well in partial light, like a window, with the addition of an optical sensor to trim the LED’s when there’s enough sun.  Thanks to David at RAB Designs and Jen and Jim at Subtle Technologies for supporting the project.

- Micah Donovan

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2 Responses to “ Food Jammers DIY basement farm: Grow Tubes for Subtle Technologies ”

  1. After the Harvest on June 15, 2010 at 10:08 pm

    Beautiful, sustainable and amazing!! You have inspired me even more to start growing more of my own food Also I used to sit in Innis Town Hall for many a film lecture so thanks for the nostalgia.

  2. on July 24, 2010 at 12:17 pm

    [...] of the food dudes, Micah Donovan, has his own blog called Somewhat Sketchy where  I recently read about his totally rad grow tubes! I love the “About” section of [...]