Rolling Hills Farm

Rolling Hills Farm

by Betsy Peirce, Produce Manager

“The word hydroponics comes from two Greek words, “hydro” meaning water and “ponics” meaning labor. The concept of soilless gardening, or hydroponics, has been around for thousands of years. The Hanging Gardens of Babylon and The Floating Gardens of China are two of the earliest examples of hydroponics. Scientists started experimenting with soilless gardening around 1950. Since then other countries, such as Holland, Germany and Australia have used hydroponics for crop production with amazing results.”  (

Eric and Fern and Jason (son) Unruh own and operate Rolling Hills Greenhouse, a nearly 10,000 sq ft facility, located NE of West Union, Iowa. They moved to Iowa in October 2010 and have been in business since March of this year, supplying the Co-op with hydroponically grown delicate salad mixes (spicy and spring) in clam shells and “living lettuce.” Living lettuce is a lettuce head with the roots still attached which helps prolong shelf life (up to 18 days).

Eric and Fern along with Jason and Titus, their sons, came to Iowa via Greensburg, Kansas. Originally Eric and Fern had come to visit their daughter who was teaching at a small rural Mennonite school in West Union. The Mennonite Community in West Union is young and small, and they felt like they could be of some use having come from a more established community in Greenburg. This, along with their longtime dream of operating a hydroponic greenhouse, caused them to simultaneously come to the realization that NE Iowa could be their new home.

While they were farming traditional crops in Greenburg (the town that was all but destroyed when a 2007 F5 tornado went through), Fern says she and Eric visited different types of greenhouses all over the US and the world (Eric does humanitarian work in Africa) long before they actually knew they were going to go with this type of hydroponics. They had definitely been interested in them ever since they first learned about them. Fern says, “I guess it was meant to be.” It is indeed apparent that the Unruhs love what they do and have thought of every aspect of their business. It is a very involved venture.

I admit that I have never been in a hydroponic greenhouse. I didn’t know what to expect so it took me a bit to understand exactly how it all functions. When we walked into the very clean, soil-free environment, I was struck by the beauty of the 15,000 colorful lettuce heads, multiple varieties in various stages of maturity happily growing in their long trays about waist high from the ground. Fern explained that in order to receive the proper nutrients in which to raise lettuce, a sample of their well water was sent to an agricultural lab where it was determined what other nutrients needed to be added to create a “perfect mix” for growing lettuce. A hydroponic nutrient solution contains all the elements that the plant normally would get from the soil. The Unruhs also grow herbs and are experimenting with some other crops like green beans and snap peas.  So far they have had luck using the same nutrient mix for all their crops.

The hydroponic system they use (there are many) is called an Ebb and Flow. “The plants are all started in a growing medium called Rockwool. Horticultural Rockwool is produced from volcanic rock and limestone. These components are melted at temperatures of 2500 degrees and higher. The molten solution is poured over a spinning cylinder, comparable to the way cotton candy is made, then pressed into identical sheets, blocks or cubes. Rockwool holds 10-14 times as much water as soil and retains 20 percent air. Thus making it a very common growing medium in hydroponic production. (

Each Rockwool block is planted with lettuce seeds and germinated in trays, similar to the soil blocks used in gardening. Once the seedling is big enough they are broken apart and “planted” into the long trays set at an angle where the roots are fed several times per day with the nutrient solution. The entire maturation length of the plants changes depending on the season. It takes as little as 4 weeks in the summer, 6 weeks in the autumn and more in the shortest days of winter. All the water and nutrient solution that is used in the Rolling Hills system flows through the trays and back into the underground tank where it is tested automatically and “rebalanced” by adding in the nutrients that were drained by the plants. A computer controls all aspects of the process. It tests the temperature, Ph balance and the fertilizer and digitally adjusts the water for the next cycle.  The benefit to using and Ebb and Flow System is that it is an active recovery system. The water is constantly recycled and flooded through the trays keeping the roots properly fed and oxygenated. The Unruhs completely drain and clean the entire system once per week and start the process all over again with fresh water and nutrient mix. They also test regularly for pathogens such as E. coli.

The environmental atmosphere in the Rolling Hills greenhouse is also carefully monitored. First of all, the computer controlled system has an alarm for each and every aspect of the process (temperature, humidity, pumps or fertilizer mix) should one or more systems fail. For environmental control, there are shade cloths to pull across the top of the structure on hot days. The shade cloths are also utilized on cold days to lower the ceiling and save on heating costs. There is a “wet wall” on one end of the structure which looks like a porous radiator. Water runs through the wet wall cooling the air as it is drawn through it. Levered vents on the other end of the structure open and close to allow air to circulate and a large fan also aids air circulation.

The Unruhs are dedicated to making their operation as sustainable as possible, given the limitations of a year-round greenhouse in Iowa. They currently have LP heating the greenhouse but are in process to convert to wood heating with an LP back-up. They use beneficial insects to control pest outbreaks by buying ladybugs and other beneficials from the Netherlands (a country that is covered in greenhouses). They use an insecticide approved by the Organic Standards for other pest outbreaks.

The Unruh’s have found their produce to be quite in demand and say that they are currently filling only half of the orders that they could fill if only they could double their space. Fern stated that they need customer loyalty year round to be able to continue. They keep their prices low in the summer to be able to compete with the local pricing, but the cost of their inputs goes up in the winter, and they must raise prices in order to offset the increased costs.  They are hoping to sell their Kansas farm so they can buy land to farm crops and double the greenhouse space someday, but until then the family is covering their costs and paying themselves a little.

At the end of our tour Fern began giving me samples of some of her wonderful greens. I tasted the sweetest, most delicate arugula and parsley with no bitterness. The lettuce is sweet and tender – like the first tastes of spring growth, only in September. We are certainly lucky that the Unruh’s answered their call to Northeast Iowa and we hope we continue to benefit from their “Water Labors.”