Clayton Timm holds up a raft of summer crisp lettuce, nearly ready for harvest at his family’s new aquaponics farm, Green Leaf Farms of Chetek. Behind Timm are fish and filter tanks where tilapia are raised.

Locally grown, organic romaine lettuce, summer crisp lettuce, kale, swiss chard and basil will be available all year round thanks to a new high-tech farm in Chetek.

Green Leaf Farms of Chetek, started by Clayton and Kelly Timm, officially opened on Oct. 21, located in the greenhouse building on CTH M, about a mile north of Chetek.

The farm uses a process called aquaponics, explained Clayton Timm. By combining aquaculture—raising fish—with hydroponics, or growing plants in water, they can grow produce year round without artificial fertilizers, pesticides or herbicides and no dirt.

The process starts with 1,000 tilapia in four, 500-gallon tanks. They are fed fish food and they drop waste and expel ammonia. Natural, beneficial bacteria in the system break down the waste, leftover fish food and ammonia, eventually turning it into nitrate, which is a nutrient plants need to grow.

This nutrient-rich water is sent to 56-foot long troughs where lettuce plants are imbedded on floating rafts with roots hanging below in the water. The plants take up the nutrients, filtering the water before it returned to the fish tanks.

Each part of the system—the fish, beneficial bacteria and plants—benefits from another part. The only input is fish food, raising fish and planting new plants.

Timm plants lettuce seeds in special trays and as the plants grow, they are transferred to larger trays before finally being transferred to the floating rafts.

New plants are added to the rafts at one end, and 36 to 42 days later, trays of mature heads of lettuce are harvested at the other end. At maximum, the system can produce 70 heads of lettuce a day and 45,000 or more heads annually.

Summer crisp is available now, and romaine will be available again by December.

Next to two troughs for lettuce, is another one filled with clay pellets, where swiss chard and kale were growing in. Other trays held basil. He’s been producing and selling a few bags of those each week.

Two smaller fish tanks are the fish nursery, are where tiny tilapia fry are grown to adult size over three months. They spend six months in the large tanks as adults.

“They are the hardiest and quickest growing fish,” Timm noted. He added that the University of Wisconsin-Stevens Point researched using walleye instead of tilapia, but they take longer to mature, he said.

Eventually, the fish will be harvested and filets sold as well, and a new batch of fish will take their place. Tilapia filets will be available by mid-January.

Timm said a friend had brought up the idea about ten years ago, but he and Kelly hadn’t considered it until recently. At Thanksgiving last year, they discussed it, and decided if they could make it work, they’d try it. It was also a project he worked on with his son, Alex.

Timm admitted he didn’t have that much of a green thumb, but along with a three-day master class with a company partnering with UW-SP and a plethora of informational videos online, he learned all he could about the process.

Green Leaf is selling 15 heads of lettuce to the school a week, and also selling produce to Gilligans and KJ’s Fresh Markets in Chetek and Barron.

“It’s clean and never been in any dirt,” Timm noted. “No waste, it’s all edible.”

Asked what is plans are for the business, Timm said the goal was to make it bigger.

It’s no surprise—they are in the business of growing.

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