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Clarksville produce supplier anything but traditional

From the THANK A FARMER: Featuring Southern Indiana farmers series

Hydroponic system yields plants year-round

  • 3 min to read

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CLARKSVILLE – Things at Grateful Greens are done differently. Plants from the small operation just southwest of the Interstate 265/65 interchange never touch soil. 


Jeff Walker has spent almost all his life not growing plants.

The 53-year-old Louisville native earned his bachelor’s degree in business from the University of Kentucky and a master’s degree in international economics from The Patterson School. He has worked for the U.S. Department of Commerce and a fortune 500 company in New York, and has spent the better part of 17 years in Asia in various high-ranking roles in the insurance business.

“... and then I started selling lettuce,” Walker joked.

His father bought Grateful Greens in 2008 and moved it to Clarksville from Louisville a year later.

“We were facing some business challenges recently and that’s when my family asked me to come in and take a look and see what we could do,” the younger Walker said.

Now, instead of walking into a skyscraper in Hong Kong or Indonesia every day to head an insurance company with more than 7,000 employees, Walker strolls into the modest building off Addmore Lane to manage his five employees and make sure the nearly 70,000 plants in the greenhouse are getting what they need.

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Grateful Greens Managing Director Jeff Walker pulls a row of bibb lettuce for inspection. 

“I never in my life though I’d be growing lettuce," he said. "At the same point, I never thought I’d be an insurance executive in Indonesia. So, I’ve always looked at things that you go where life takes you.”


Grateful Greens is a hydroponic operation meaning, aside from a few edible flowers grown primarily during the fall, the plants are grown entirely in water.

The key to the system is a network of tanks, underground plumbing and tubing that delivers water infused with essential vitamins, such as potassium, calcium, zinc and iron, to the plants constantly.

Whatever the plants don’t soak up circles back to the beginning.

“Sometimes a plant wants more calcium, sometimes a plant wants more potassium,” Walker noted.

Each plant’s life cycle starts when it’s dropped by hand into a “medium.” Whatever is harvested is reseeded that same day.

After the seeds germinate, roughly a week, each sprout is “plugged” into a hole on a white plastic channel. Each channel contains between 17 and 32 holes, depending on the “vertical nature of the crop” according to Walker.

Chives will go in a channel with 32 holes. Bib lettuce, a channel with 17.

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Water droplets cling to blades of wheatgrass growing beneath red and blue LED lights inside the farmhouse at Grateful Greens in Clarksville. The plants respond differently to varying colors, using a color mixture to provide for optimal growing conditions and production from each seedling. 

Walker said this time of year, most greens are ready to harvest 35 to 40 days after they are plugged.

Wheatgrass, typically purchased by juice bars and recovering cancer patients, grows on or under burlap, under blue and red LED lights and with fans circulating air through the young blades — the best conditions, Walker said.

More unusual greens such as micro celery, micro cilantro and tangerine lace grow on biostrate felt.


Technology plays a key role in the keeping the plants thriving in the greenhouse year-round.

“Because we have this controlled environment, we are not dealing with the weather elements outside or the critters or whether the soil has the right nutrient mix, whether it’s raining … we know once we have the recipe mix together, we are always going to have a superb product,” Walker said.

In the greenhouse, one system keeps the temperature between 70 and 85 degrees Fahrenheit and humidity around 55 percent.

Another system keeps track of the pH level and electrical conductivity of the plants at all times.

Walker points out that one security camera within the farm building is zoomed in at all times at the pH tracker. He can check the video feed from his cell phone from anywhere in the world.

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Hydroponics uses water enriched with minerals to feed the plant system and to maintain the chemical balance for optimal plant growth. Without the use of soil, the plants sit about 4 ft. off the ground with space for water to run down from the slanted rows containing the plants, collecting below and returning to the greenhouse's filtration system. 

“I’ll constantly be checking, even if I’m not here,” he said. 

Lights — 240 of them — hang overhead so that in the winter on shorter, overcast days, the plants still get all the light they need to grow. The electric bill can run as high as $30,000 in those months, Walker said, but he is striving for “consistency, reliability, availability.”

The “lighting doesn’t replace natural sunshine,” but it can help to produce a product year-round.


Produce from Grateful Greens is sold throughout Louisville and Southern Indiana. High-end restaurants that boast farm-to-table style dining, grocery stores and produce distributors purchase the vegetables and herbs.

According to Walker, he moves between 50,000 and 60,000 heads of lettuce every month.

The greens often are delivered just hours after they are harvested, with root systems still in tact to ensure freshness and longevity.

Walk-ins are encouraged, too. Around 12 to 15 customers come in weekly to purchase fresh produce, something Walker welcomes.


Moving forward, Walker just sees things getting better from here.

“We have some bigger designs for the business,” he said.

Building on existing customer relationships and diversifying stock by adding new plants are just some of the plans Walker has for the business.

A membership-based home delivery service is in the works, as well; it's expected to launch this fall.

“Our desire is to have this company to be a much larger scale organization ... we still have an additional three acres available here to expand. We have the desire and we have some hard-working people. I think we’ll get there… we can fill three acres. Our family name is behind this business and that means a lot to us,” Walker said.

Education Reporter

Erin Walden is the education reporter for the News and Tribune. She studied journalism at the University of Cincinnati. Send tips and story ideas to