Aeromaster Compost Turner an integral part of quality humus production

Penn-Valley-Farms-Composting-1119by Jon M. Casey

While a compost turner is routinely a peripheral component in the overall production of quality compost at many composting operations, at Penn Valley Farms, the Aeromaster PT-130 compost turner is critical to the manufacturing of their premium product line, aptly named Aeromaster Humus Compost. For many compost producers, the process is simple. Windrows of ground yard waste (mulch) is mixed with manure or other organic waste and is allowed to naturally decompose, being turned once or twice before becoming what is considered a final product after eight to twelve weeks on the composting pad. Often, this composting method is supplemented with food waste, vegetable waste and manure of various kinds. Even so, ordinary compost production does not result in a quality material like the Aeromaster Humus, formulated at Penn Valley Farms.

For the typical landscaper or gardener, most of the aforementioned products are routinely acceptable. For the discerning end user however, one who is looking for the benefits and plant growing qualities that only a premium humus can provide, the precise formulation of composted humus material, formulated using the Aeromaster Humus Technology offered by Midwest Bio-Systems and Penn Valley Farms, is what the Kellers are striving to achieve.

We met up with Bob and Jonathan Keller in early August as they were finishing their windrowing in preparation for the 2016 season. Jonathan said they begin building compost in April and finish up for the season by late August. They find that the cooler temperatures of central Pennsylvania falls and winters, slows the composting process to the point where they need to have their final windrows formulated and in place about two months before winter. In this way, they are able to spend the winter months bagging and storing the products they plan to sell in the next season.

Currently, they feature bagged products including Aeromaster Premium Blend, Raised Bed Garden Blend for square foot gardening, distributed by Your Garden Solution, Greenhouse Media, a product distributed by Keystone Bio-Ag, LLC and a product called Nature’s Trophy Blend, distributed by Nature’s Outdoor Solutions. This product is a soil amendment designed for deer food plots that enhances the grazing quality of the land to improve antler growth.

How it all started

Bob recalled how his initial desire to begin composting came about because of excess manure on his farm and his commitment to improving the farm’s soil makeup. That was in the early 1980s. Eventually, he converted the farm from conventional to organic farming in 2000.

He said this 95-acre farm was originally part of a 540-acre homestead that was settled in 1735, by Peter Reist, a Swiss immigrant. In 1933, Bob’s (J. Robert Keller) grandfather bought the farm from descendents of the Reist family. At the time, tobacco was an important cash crop, but by 1950, the Keller family had eliminated that crop and produced the usual crops for a commercial beef operation.

In the 1960s and 1970s, they expanded production by adding a 250-head cattle feedlot and a 68,000-layer facility was the focal point of the operation. By the 1980s however, Bob began to realize that the application of manure on their crop fields, was beginning to increase the potassium and Phosphorous levels in the soil. That was when Bob said he began considering his options so that he could continue to farm without damaging the soil with excessive manure and having to worry about impending nutrient management regulations in the coming years.

He said in the 1990s, he began experimenting with composting cattle manure as a means to manage his farm’s manure output. His idea to compost the cattle manure not only provided better soil nutrients but it also met governmental regulations that affected transporting and using raw manure application. In the early 1990s, he learned about Midwest Bio-Systems and their emphasis on soil biology with regard to utilizing compost. That was when he purchased his first compost turner and began making compost as a manure management tool.

In 1997, Keller said he made the commitment to going Certified Organic on the entire farm, taking the three years that are required to make this change. As part of that commitment, he divested himself of the cattle operation. “We did not have the available land for feeding the cattle on pasture that is required for organic beef,” he said, referring to the 95 acres that he currently farms as a certified organic farm. “We had built the new aviary poultry house for laying hens to provide organic eggs as part of our organic production.”

Today, they grow Alfalfa, corn, soybeans, wheat and include sorghum Sudan grass as a cover crop as part of a seven year rotational program. Their organic crops are sold to organic farmers in the area and the wheat is used to make organic flour for bread and other baked goods. The sorghum Sudan grass is used as feedstock for composting while wheat straw and cornstalks are an ingredient in the composting process as well.

During that time, the humus-composting segment of the farm continued to grow, becoming more than a manure management operation. “As others could see the success we were having with our crop production and weed control by using our Aeromaster Humus mineral blends, other people began to request our product,” he said.

“We began formulating humus based soil amendments for Keystone Bio-Ag in 2011. Keystone Bio-Ag is a local distributor of the Greenhouse Media product. More recently, we have provided bulk sales to landscapers and local farmers who are looking to improve their soil biology as a way to improve yields and reduce their reliance upon synthetic fertilizers and chemicals.”

The Midwest Bio-Systems Method

Jonathan explained that after he graduated from high school, he took a job away from the farm but returned to farming after realizing that farming was where his heart was. Jonathan and Bob agreed that as part of the preparation for his return, it would be good training for him to serve as an intern at Midwest Bio-Systems in Tampico, IL. There, he could learn how the equipment works and he could learn the soil biology that their training center provides as part of Aeromaster composting technology. Jonathan said that with Midwest Bio-Systems, the overall program is more than a piece of equipment.

“Midwest Bio-Systems was founded by Edwin J. Blosser, a crop and soil consultant focused on soil mineralization,” said Jonathan. “He went to Europe to learn about composting and soil biology in the early days of the process. When he returned to the US, he eventually decided to refine the composting process by designing a compost turner starting with the end product and working backwards. That meant he would experiment with ways for the equipment to produce the kind of lift, aeration, blending and moisture application that was needed to produce the kind of humus that he was seeking. The end result is the Aeromaster Compost Turner line.”

“Over the years, we have worked with several formulations of ingredients in our humus products to bring us to where we are today,” said Jonathan. “We have found that our secret to success is the correct blend of ingredients and inoculants combined with the correct levels of moisture in making our compost. By keeping the moisture and temperatures at the appropriate levels, we can produce quality humus in as little as 10 weeks. Most composting operations need 12 to 16 weeks to have a finished product. I would say we turn a single windrow at least twenty-five times during its various stages of development. We put our Aeromaster PT-130 to good use.”

Keller said the addition of the WT-1775 Aeromaster Water Trailer is an integral part of the process. “We can apply water and inoculant in precise levels to meet the need of the individual windrow,” he said. “We take daily moisture, CO2 and temperature readings on all of our windrows to maintain optimum quality throughout.”

Jonathan said he enjoys working with his family on day-to-day operations. He said his sister Karen oversees the laying hen operation and his sister Stephanie helps by driving equipment when needed. “She’s a very good equipment operator,” he said.

“Jared Harnly works with us full time as our foreman and Jerrod Steager is a part-time employee who is still in high school. Together, we do what it takes to make Penn Valley Farms and our Aeromaster Humus products a success.” For more information on Penn Valley Farms, visit their website at For more information on the Aeromaster equipment line or composting workshops, visit


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