POWAY, Calif. (CBS 8) -- Growing vegetables in a home garden can be a rewarding and healthy hobby. It also takes a lot of water. But there might be a better way.

Aquaponics is a type of garden that is not only water efficient but also organic, thanks to fish poop.

Poway resident Andy Smith designed a system for his backyard using a 275 gallon fish tank, two gravel grow beds, and a greenhouse covering.

He loaded the fish tank with 33 tilapia fish.

The system uses a low-voltage pump to circulate the fishy water as fertilizer to grow vegetables in the greenhouse.

“You can see the water, although it's a little brownish in color, it's very clean,” said Smith.

He said the system cost him about $1,500 in materials, which included a sump tank and homemade water filter.

It's a closed loop system that's about 95 percent water efficient, he said.

“The water is completely re-circulated. It's enclosed. The only water that's used is by the plants and a little bit of evaporation that you get,” said Smith.

The result is really fast growing vegetables, organically fed.

“It's really low maintenance. I basically feed the fish – my son feeds them in the afternoon – and I harvest the vegetables,” said Smith.

And the vegetables are big. “Look at the pepper, I mean it's absolutely huge,” he said.

Smith said it costs him about seven dollars a month to run the pump.

The only additional cost is heating the water because the fish will die if the water temperature drops below 66. Smith set up a homemade, solar water heating system.

“It's is a natural ecosystem. It's self-contained,” said Smith.

An ecosystem that, one day, will also provide protein for Smith's family because tilapia fish are edible.

“I haven't eaten them yet, soon, in a couple months they'll be big enough,” said Smith. “Fish tacos, for sure!”