A Simple Solution

Image Gallery Photo by LEIGHSUTERLAND

ORGANIC HYDROPONICS :

From Self-Reliance by permission of the Institute for Local Self-Reliance, 1717 18th Street N.W., Washington, D.C. 20009.

The author has requested feedback from anyone who tries the solution described in the following article. Address your response to: Miranda Smith, ILSR, 1717 18th St. N.W., Washington, D.C. 20009.

To many, the idea of organic hydroponics seems like an impossible contradiction. Hydroponics, the growing of plants in a medium other than soil, usually utilizes a chemically derived nutrient solution. Organic gardeners, as a rule, do no like hydroponics: for those who love the soil, the prospect of plunging elbow-deep into a gritty mix of parlite and vermiculite is not very inspiring. Nor is brewing up a batch of Hy-pon-ex or Miracle-gro. How-ever, as an enterprising group of urban gardeners in Montreal has discovered hydroponic food production need not rely upon a chemical nutrient solution ... and, under the unique conditions of rooftop farming in the city, soilless vegetable cultivation has distinct advantages.

THE MONTREAL PROJECT

Two years ago, the Canadian government funded an eighteen-month demonstration project in Montreal to investigate the feasibility of rooftop agriculture. The intent of the funding was the development of appropriate agricultural methods and technology so that people would be able to farm the flat wasteland above their city. The target community was the inner-city, ethnically mixed neighborhood, St. Louis Sud. Project workers taught courses in gardening and "roof maintenance" skills, so that community residents could take over the project when funding ran out.

The two gardeners who were hired to teach, research, and supervise were experienced organic gardeners who preferred to work with soil. During the first summer, the rooftop gardens were planted in earth. Over 100 cubic yards of dirt had to be carried by hand up two flights of stairs, each cubic yard weighing between 195 and 270 pounds. The soil then had to be loaded into carefully positioned containers, so that the stress on the roof would be minimized. Even though the roof was strong and could support 80 pounds per square foot, still much of the "wasteland" had to remain uncultivated. If a lighter medium had been used, more rooftop space could have been utilized for food production.

During that first summer, the differences between ground level and rooftop agriculture became apparent. Container soil dried rapidly and had to be watered daily. Nutrients leached out with every rain and the plants had to be side-dressed with a variety of fertilizers at least every three weeks. Since the relative populations of soil micro-organisms and animals are greatly reduced in rooftop containers, their role in soil regeneration in the rooftop project was less significant. Earth worms, though they lived well in the boxes, could not bring minerals back into the earth from the parent rock because there were no parent rocks. By July, the root systems had become potbound, filling the entire container. It was found that insect problems occurred more easily on the roots than on the ground it strict care was not maintained. It began to look as if organic container gardening could never be more than a poor cousin to ground level organics.