Micro Solutions for Urban Agriculture

PROJECT BACKGROUND
New Roots Urban Farm (NRUF) is an approximately 1/3 acre farm located in St Louis’ inner city, just 2 miles north of the arch. The farm employs bio-intensive no-till vegetable production, with an emphasis on crop rotation, top dressing, and cover cropping. In the past we have sold produce and sprouts through a CSA and farmer’s markets. Our current activities include subsistence vegetable production and selling at our neighborhood farmer’s market. We grow tomatoes, okra, collards, swiss chard, mustard greens, strawberries, peppers, cabbage, lettuce, spinach, winter squash, sweet potatoes, potatoes, beets, carrots, turnips, onions, asparagus, and leeks. Our farm was previously four abandoned city lots which we have transformed through the importation of compost and organic matter into approximately 15 raised beds an estimated 70 feet long.

NRUF practices no-till growing; only utilizes hand labor; irrigates with drip irrigation. We produce compost on site, only use organic pesticides, rotate crops, and sell all our vegetables within fifteen miles of the farm. We have been using these practices in all of the seven years the farm has been in operation.

PROJECT DESCRIPTION AND RESULTS

GOALS:
The listed objective is to provide NRUF with a small space income-generating enterprise which would supply a salary for the farm manager, thus increasing the economic sustainability of the project.

PROCESS:
We first traveled to Growing Power in Milwaukee, WI to learn how to design, build, and maintain an aquaponics system. Growing Power has been considered a leader in urban agriculture and has approximately ten aquaponics systems running. Three of us spent three days there working intensively with their aquaponics specialist.

Back in St. Louis we began designing the system and adapting it to run on solar panels. We quickly realized a major limitation, and perhaps flaw, in the grant proposal. There was not a precedent, that we could find, for running such a system on solar power. To put it briefly, we had to match the power we might get in 5-7 hours of sunlight with the power needs of a pump that had to run 24 hours a day. And hopefully provide enough of a reserve for cloudy days. The pumps used by Growing Power were too power hungry to even consider in our system. Thus we sought out 2 small DC well pumps which proved to not work in such a system. In the end, we knew we were cutting it close. To build a really reliable system we needed either an additional solar panel and battery or a grid tie-in that would automatically switch over when the power got too low. The risk in having a system shut down is that you can lose all the fish in less than 24 hours. We built a system with approximately 100 square feet of bed space, a 300 gallon filtration bed, and a 500 gallon fish tank. The system us a circulating system: the fish tank gravity fed into the filtration bed; from here water was pumped up to the growing beds; which then gravity fed back into the fish tank.

We had planned to raise tilapia because of their ability to survive in poor water conditions and fast growth abilities, thus we retrofitted an existing greenhouse to house the system. In the growing beds we planned to grow high value sprouts (sunflower, radish, arugula, beet) which would be harvested every 7 to 12 days (depending on weather and variety). Although we needed to expand our market to meet our income needs, we already had an established market for our sprouts at a local farmer’s market and one restaurant since we had been selling sprouts for 2 years previous. Since we always sold out at the farmer’s market we sought to first increase our production there and then expand into selling to more restaurants.

PEOPLE:
Growing Power – Milwaukee, WI: Three farmers traveled to Growing Power to work with the aquaponics specialist there. Here we covered the hands on maintenance and construction techniques, but also the overall design concepts. We were beginning to design our own system as we learned and we’re able to get feedback from the specialist there. We were able to see at least ten different systems running of various sizes and designs.

Home Eco – A local green home store aided us in selecting the solar panels and helped locate pumps that would meet our needs. We ordered the solar panels, battery, charge controller, and pumps from Home Eco.

RESULTS:
The aquaponics system construction was completed late fall 2008. Too late to introduce tilapia, we did several test runs after completion. The first problem we ran into was with the pumps. The pumps need to be primed before they would pump water through the system. Although this problem was temporarily resolved, a permanent solution remains undetermined. I believe it can be resolved by putting in-line hand pumps above the pumps to manually prime them.

The system was up and running for about a week at a time that fall, when it shut down two different times due to lack of power from the solar panel and batteries (after consecutive cloudy days). Here it became apparent we needed to supply backup grid power or add additional solar capacity. This problem still needs to be addressed and would probably add significant additional cost to the original budget.

In addition to these technical issues, that could be solved with additional money and time, our project ran into problems related to our own labor capacity at New Roots. We realized that caring for fish in an intensive system required consistent and constant monitoring, which was beyond our labor capacity. At this time, as a farming collective, we had decided to scale down our project due to individual life circumstances and financial needs (that the farm couldn’t provide).

Although the system was never up and running to its full capacity, the presence of the system on our farm continually prompted a lot of interest and dialogue from our farm visitors during the numerous tours we host during each season.

We continued to produce sprouts using our previous methods throughout 2008 and into 2009, but it remains to be seen whether the growing beds would provide too much moisture, causing the seed sprouts to rot. This is something that we began to wonder but haven’t yet answered.

Before applying for a similar grant, we think it would be utterly important to better understand our long term capacity and vision as a farm.

DISCUSSION:
Even though we never raised fish, we learned a tremendous amount about designing and constructing an aquaponics system.

As stated above, we learned we needed to better understand our long range capacity and direction before applying for a two or three year project.

A disadvantage of the original construction process is that it took significant labor away from other parts of the farm operation.

We still believe an aquaponics system has a lot of potential to expand income for a project like ours. But it does carry a significant risk because (as demonstrated while we were at Growing Power) if your pumps shut down for too long you can lose all your fish in less than 24 hours. One significant difference between an extensive system and this intensive growing system is the stability of the system depends on electricity and pumps running 24 hours a day.

PROJECT IMPACTS
We can’t really evaluate the impact of this project since we never got the system fully operational.

OUTREACH
Hundreds of people have seen and inquired about the aquaponics system since construction first began. New Roots has many visitors and host farm tours throughout the year. We are always sure to explain and show the aquaponics even in its non-operational state. A article was written by Chris Olliges and included in our 2007 quarterly newsletter.