Karl Hammer checks the temperature of a composting pile. Guaranteed weed-free, Vermont Compost products are “cooked” at 131 degrees Fahrenheit or higher.

Karl Hammer is passionate about compost. He values it so much that he spent many years and many dollars trying to persuade Vermont state authorities that composting is inherently an agricultural activity and should be regulated as such. Currently, Hammer and 10 employees make compost on about 6 acres of his 47-acre Montpelier farm (the remaining land is in pasture and woods) and at a 13-acre leasehold on a large dairy farm nearby.

Feeding The Soil

A basic concept of organic agriculture is: “Feed the soil, and the soil will feed the plant.” This, together with the precept that “Nature never farms without animals,” is at the core of all Vermont Compost Co. activities and products. “Good, certifiable organic growing media is difficult to find,” says Hammer. “We make some of the most dependable.”

The products Vermont Compost (www.vermontcompost.com) makes consist of various combinations and proportions of materials blended to feed soils and plants. Some of the ingredients, such as some of the manures and old bedding hay, are generated on-site; others, such as food wastes, come from relatively local sources. Put simply, materials are deposited at the top of the hilly Montpelier site, are mixed and processed in the middle, and come out at the bottom ready for testing and bagging or bulk shipping. Bags are available in sizes from 6 to 60 quarts; bulk shipments range from pallet to trailer-load.

The basis of all Vermont Compost soil mixes is Manure Compost. Like all of the company’s products, it is made of ingredients approved for certified organic production and includes cattle and horse manure purchased from two local dairy farms and eight local stables combined with avian, mule and donkey manures from Vermont Compost’s own chickens, mules and mammoth donkeys. It also contains hardwood bark, primarily maple and yellow birch, from trees cut in Vermont, milled in Quebec (a common practice), and returned to Vermont as dimensional lumber and bark. Late-cut hay is included for its high carbon and silica content, and because its diverse seeds are desirable as feed for hens. Spoiled corn and grass silage help control pH.

Food residuals are deposited in a pit (foreground, with chickens). Behind the pit is the roost house, and to the right are compost processing and bagging facilities.

Food residuals (remains from grocery stores and restaurants) have been included in Manure Compost since 1998 and are a part of all Vermont Compost products. Grocery stores and restaurants save leftover food in 48-gallon roll-around totes that are collected by the Central Vermont Solid Waste Management District in a roll-off truck and inspected for contaminants by the driver. The totes are pressure-washed in an onboard hot water system before they are returned to the grocery store or restaurant. As soon as food residuals arrive at Vermont Compost, they are blended with a mix of bulking material. The company’s laying hens then pick through the mixture for nutrients, including insects, and deposit their manure.

Next, mature compost is added to inoculate incoming material. “Cooked” to at least 131 degrees Fahrenheit, Vermont Compost products are guaranteed to be weed-free. To control moisture, sphagnum peat moss is added to bagged products. Leaves, a common component of compost, are not a part of Vermont Compost products because of the difficulty of finding clean leaves in large quantities.

Chickens everywhere

Avian manure is an integral part of Vermont Compost. Where there is Vermont Compost in the making, there are chickens foraging for insects and adding their waste. The shallow pit where food residuals begin their journey through the composting process serves as the chickens’ primary source of food. Like people, chickens have individual food preferences, notes Hammer. The chickens are fed no grain. They forage outdoors all year, eating the food residuals, grass and spoiled silage. At their peak in 2007, the 1,000 laying hens, primarily Australorps (the Australian take on the Orpington breed), produced 15,000 dozen free-range, fertile eggs. Roosters are Light Brahma and Australorp purebreds and crosses. In their laying roost house, chickens bed on dry hay. Hammer prefers late first-cut hay because it is more porous and has a higher carbon content, and because chickens like the seeds.

“Making compost is a challenging craft-and a big responsibility,” says Karl Hammer, founder of Vermont Compost Co.
Photos by Kathleen Hatt.

A few donkeys and mules

Growing up and working on the farms of his family’s neighbors in Vershire, Vt., Hammer acquired his love of both farming and draft horses. When he moved to Spain in his late teens, he was introduced to farming with donkeys and mules. Hammer values both of them so highly that an image of a donkey became the logo of Vermont Compost. His preferred donkey is the Catalonian mammoth, the breed King Charles III of Spain sent to George Washington. “Named Royal Gift, his gift value was questionable,” says Hammer. “He was not a ready breeder.” Mammoth donkeys of today are a combination of as many as five main breeds, including Catalonian, Andalusian, Majorcan, Maltese and Poitou. Mammoth jacks are indeed large, standing 56 inches and taller; jennets are 54 inches and above. The mammoth jack and jennet at Vermont Compost are kept for draft, roadwork and breeding – and, of course, manure. They also serve as a symbol of the future solar-powered farms to which Hammer aspires.

Biodynamic preparations

To guide the particular decomposition processes within the composting mass, Vermont Compost products are made with biodynamic preparations. As described by Rudolf Steiner in 1924, seven herbal preparations frequently used in medicinal remedies are employed in making biodynamic compost. These include yarrow blossoms, chamomile blossoms, stinging nettle in full bloom, finely chopped oak bark, dandelion flowers, valerian flowers and horsetail. Except for preparation 507 (valerian mixed with water), preparations are buried at specified intervals within the compost heap. Preparation 507 is sprayed over the compost surface.

Chickens at work. In 2007, 1,000 Australorp and Australorp cross layers at Vermont Compost produced 15,000 dozen free-range, fertile eggs. Their manure is an integral part of the company’s compost.

Is compost an agricultural product?

Designed to protect the state from development pressures, Act 250, the Land Use and Development Act of 1970, followed the opening of two interstates, which made Vermont more accessible year-round. Vermont was concerned about protecting its environment, community life and aesthetic character. Among the specific conditions Act 250 sought to prevent are air and water pollution, soil erosion, congested roads, and degradation of wildlife habitat, agricultural and forest soils, and earth resources.

In 1993, Hammer began making Vermont Compost products, and in 2006 he was cited for noncompliance with the provisions of Act 250. It was not until 2010, five expensive years later, that the state of Vermont finally issued an Act 250 permit to cover a portion of the farm deemed “commercial.” Hammer says, “Anyone contemplating composting on a farm in Vermont is well-advised to be aware of Act 250, especially if the farm’s primary income might come from composting.”

In addition to this environmental law, Vermont Compost must also comply with agricultural regulations. A new solid waste law, Act 148, mandates the diversion of all recyclables from landfills by 2020. Says Hammer, “It remains to be seen how this unfunded mandate will be implemented. Estimates are that Vermont currently has only 15 to 20 percent of the compost-making capacity required to meet mandated goals.”

Product testing

Vermont Compost products are tested both in the farm’s greenhouse and by university soil science laboratories, primarily the University of Vermont. Bioassaying in the farm’s greenhouse is ongoing. To check the effectiveness of growing media, plants are started weekly in Vermont Compost products and evaluated for rate of growth and general plant health. The greenhouse lab also measures the pH (acidity), EC (electroconductivity), NO3 (nitrate), moisture and density of growing media, with the goal of finding consistent scoring, not radical change. If radical change is noted, the product is pulled before it is distributed to growers. Products have been tested in vegetable fields at Vermont Compost’s Main Street farm since 1994. Several hundred of the region’s best organic growers also field-test products.

Windrows of blended compost are turned regularly.

Continuing to grow

For many years, growers at Vermont Compost have added a blend of three kinds of stone dust to the company’s Compost Plus container and transplant booster mix. This year was the first that the blend, StoneSweet, was available for sale. The mixture is 75 percent stone by weight and 25 percent compost. It is useful in long-term soil remineralization, and is effective in potting soil, greenhouse and field applications.

Plants are started weekly in the Vermont Compost greenhouse and evaluated for health and rate of growth.

From a mostly local operation to a company that supplies many of the professional organic growers in the Northeast, Vermont Compost has grown to supply customers as far away as the Upper Midwest. Among the Illinois, Iowa, Wisconsin and Minnesota growers using Vermont Compost products are the area’s six largest CSAs. Says Hammer, “We have found that excellent compost-based potting soil can sustain not only the cost of the product itself, but also the cost of trucking.” Shipping costs from New England, the end of the supply chain, to points west are reduced by trucking companies to avoid returning trucks empty.

The roost house at Vermont Compost’s Main Street farm in Montpelier.

“Media is the foundation of successful plant production,” says Hammer. “It often costs less per unit than the plants growing in it.” He finds that it is more profitable to develop systems to control the costs of water, heat and labor than it is to economize on the cost of productive growing media.

Food residuals, an integral part of Vermont Compost products, are deposited in this pit in which chickens forage and deposit their manure.

Of composting, Hammer says, “Making compost is a challenging craft – and a big responsibility.”

Kathleen Hatt is a freelance writer and editor and a frequent contributor to Growing. She lives in Henniker, N.H.