Saturday, April 30, 2011

Backyard food security

Here at Community Cultivators we like to highlight those folks who are really taking the ideas of sustainability to new heights. The backyard of Denton Weaver's home in Northeast Austin is a prime example. Through the use of recycled materials, a strong imagination and a vision for highly productive food systems, Denton has created something we can't help but recognize as a revolution in local food security.

More than just a backyard garden, Denton looks for ways to put our waste to work... producing food for himself and the community. In what would otherwise be an average backyard, Denton has begun to explore new and creative ways to produce a large amount of food in a very small space. He does this through an innovative system known as "Aquaponics".

Aquaponics takes the familiar systems of Aquaculture (farming of fish) and Hydroponics (plants grown in liquid medium) and bridges them together to create a closed-loop system that produces almost no waste and is capable of unbelievable productivity. Perhaps the most astounding and promising aspect of this bio-integrated method of food production is the incredible lack of water being used compared to conventional gardening systems.

In a conventional garden, you might have to water daily to keep your plants happy and productive. Much of this water seeps through the soil or evaporates before your plants can put it to use. Often times this escaping water takes many of the vital nutrients, those essential building blocks of healthy plant growth, with it as it leaches away. The "closed-loop" water circulation within an aquaponics system resolves this loss of vital nutrients and water through a symbiotic relationship between plants and fish.

In aquaponics, water is continually filtered through gravel beds where rhizobacteria and plant roots strip out the fish wastes, such as ammonia, nitrates, nitrites and phosphorus, that would otherwise build up and become toxic to fish. In turn, these fish wastes serve as liquid fertilizer for plants. Very little water is lost to evaporation and, unlike most traditional gardens, the water is continually recirculated requiring only 10% of what might be used to irrigate the same amount of produce in a typical garden.

Denton prepares his floating-raft grow-bed system in the
repurposed hull of small sailboat.
Looking something like a Rube Goldberg machine for gardeners, Denton's backyard system is built largely out of recycled materials.

"I found the old miniature sailboat hull on the side of the road with a 'free' sign on it!" Denton happily exclaims. "It just worked out that I was looking to experiment with a floating-raft design. It's my sunken boat garden!"

"The fish tank is a large sand filtration system for natural swimming pools I recovered from the dump. I'd say about 90% of the materials were on their way to the landfill."

There are many challenges to designs such as this and Denton has spent a considerable amount of time experimenting and retooling his designs.

"It's all a work in progress," he concedes. "We've just started to establish the grow-beds and we're still looking to find more fish."

Currently, Denton has only a single fish swimming around in his fish tank with a plan to add several more as the system stabilizes.

"Even with a minimal amount of fish solids, we've still managed to propagate several tree cuttings and the root systems of our water-loving lettuces are really healthy."

"Eventually I'd like to have several varieties of fish and other aquatic life. It's all about diversity and trying new things," he says with a smile.

There are a lot of reasons to appreciate that motto and it's one that Denton lives by.

"Soon I'd like to have enough food to start selling at the farmers market but, more than that, I'd like to show others how they can grow a ton of food in their backyards without a lot of waste."

No comments:

Post a Comment